Hi Nicolás,

It is possible to repackage any bootstrap theme to be installed with Odoo as a module.

Basically you would need to repackage the "building blocks" of the external bootstrap theme that you would like to use into odoo snippets using the snippets.xml file found in your theme folder under the folder called views.

I am currently working on a modification of the theme_clean module with a custom bootstrap theme and can therefore provide you with some basic instructions on how to modify this theme to include your own snippets, javascript and css.

Installing the design-themes repository:

1. Clone the design-themes repository into a custom addons directory (I created /opt/odoo/custom/addons as my odoo installation is at /opt/odoo/odoo-server/addons):
   1. sudo git clone https://github.com/odoo/design-themes.git /opt/odoo/custom/addons/
   2. add this addons directory to your odoo-server.conf or openerp-server.conf file:
      1. sudo pico -w /etc/odoo-server.conf
      2. find the line "addons_path" =  and add a comma after your default addons directory and add your new custom addons directory. The line in my .conf file looks like the following:

         1. addons_path = /opt/odoo/odoo-server/addons,/opt/odoo/custom/addons

      3. Restart your odoo or openerp-server.

   3. Login to Odoo as the admin user and go to Settings >> Update Modules List and then click the red Update List button

   4. you should now be able to find your new themes for installation. Both theme_clean and theme_zen should be working on the latest version of 8.0 (RC1)

Copying the theme_clean module to create your own new module:

1. go to your custom addons directory:
   1. cd /opt/odoo/custom/addons/
2. copy theme clean to your own theme directory:
   1. sudo mkdir theme_custom
   2. sudo cp -r /opt/odoo/custom/addons/theme_clean /opt/odoo/custom/addons/theme_custom
3. go to the views directory of your new theme:
   1. cd /opt/odoo/custom/addons/theme_custom/views
4. open up all xml files in this directory and find and replace the following snippets in each file with your theme's new path:
   1. find /theme_clean/static/ and replace with /theme_custom/static/
5. open up theme.xml in the following directory:
   1. /opt/odoo/custom/addons/theme_custom/static/xml/
   2. repeate point 4.1 (ie. find all references to /theme_clean/static/ and replace them with /theme_custom/static/)
6. repeat step 4.1 for all files found in the following directories:
   1. /opt/odoo/custom/addons/theme_custom/static/css
   2. /opt/odoo/custom/addons/theme_custom/static/js
   3. /opt/odoo/custom/addons/theme_custom/static/less
7. open up the __openerp__.py file in your  module's root directory:

   1. sudo pico -w /opt/odoo/custom/addons/theme_custom/__openerp__.py

   2. change name, description and author to reflect your own new theme's details. I did the following:

      1. {

             'name': 'My Custom Theme Name',

             'description': 'My Custom Theme Description',

             'category': 'Website',

             'version': '1.0',

             'author': 'My Theme Author Name',

             'depends': ['website'],

             'data': [

                 'views/layout.xml',

                 'views/theme.xml',

                 'views/pages.xml',

                 'views/snippets.xml',

                 'views/images.xml',

                 'views/options.xml',

             ],

             'application': True,

         }

   3. save this file and go back to Odoo's backend and then go to Settings >> Update Modules List and then choose to update list to refresh your module list available for install in Odoo 

You should now find that you are able to install your clone of theme_clean as it's own module. If you have any issues at this point look back through all of the themes files to check for replacements of /theme_clean/static/ with your own theme's new director (/theme_custom/static/).

Adding your own custom CSS to the header of your theme:

1. open up the following file - /theme_custom/views/theme.xml - this is the file that you should add all your custom theme's default header css that you'd like loaded on every page by default.
2. locate the opening <template> and <xpath> tags and insert your own css files in between the openening and close tags here (i've inserted custom.css as an example). The tags in mine were as follows:
   <template id="website.theme_chd_misc" name="theme_chd_misc" inherit_id="website.theme" optional="enabled" priority="1">
        <xpath expr="//link[last()]" position="after">
                <link href="/theme_custom/static/css/custom.css" rel="stylesheet" type="text/less"/>
       </xpath>
   </template>

3. Be sure to use XHTML not HTML in all of these xml files. If you are unsure of how to write valid XHTML simply run your HTML through a converter. I used the following online converter - http://www.csgnetwork.com/cvthtml2xhtml.html

4. You'll need to uninstall your theme, update your modules list, and then reinstall to see the changes. You will need to do this with any changes you make to your theme files if you would like to see/test the changes. I had issues with my own theme's bootstrap css files conflicting with Odoo's own. you may find that you run into issues here. If you do try removing your own bootstrap css library first and see if this helps. This will allow you to find and eliminate the issues one by one by adding them back one by one.

Adding your own custom Javascript to the header of your theme:

1. open up the following file - /theme_custom/views/layout.xml - this is the file that you should add all your custom theme's default header and footer javascript (ie. the files that should be loaded for every normal page in your theme by default).
2. near the top of the file you'll find a set of opening <template> and <xpath> tags. Inside these tags is where you should place all your header javascript. See the following for an example of adding the website_geolocation.js file:

   1. <template id="clean_script" inherit_id="website.assets_frontend" name="Clean scripts">
          <xpath expr="/t" position="inside">       
      <script type="text/javascript" src="/website_event/static/src/js/website_geolocation.js"></script>

              <script type="text/javascript">
                  (function() {
                      'use strict';
                      openerp.website.add_template_file('/theme_porto/static/xml/theme.xml');
                  })();
              </script>
          </xpath>
      </template>

3. Be sure to use XHTML not HTML in all of these xml files. If you are unsure of how to write valid XHTML simply run your HTML through a converter. I used the following online converter - http://www.csgnetwork.com/cvthtml2xhtml.html

4. You'll need to uninstall your theme, update your modules list, and then reinstall to see the changes. You will need to do this with any changes you make to your theme files if you would like to see/test the changes. I had issues with my own theme's jquery javascript files conflicting with Odoo's own. you may find that you run into issues here. If you do try removing your own jquery library first and see if this helps.

Adding your own custom Javascript to the footer of your theme:

1. open up the following file - /theme_custom/views/layout.xml - this is the file that you should add all your custom theme's default header and footer javascript (ie. the files that should be loaded for every normal page in your theme by default).
2. we'll need to add a new set of <template> and <xpath> tags to allow us to add the javascript after the closing </footer> tag in your theme. See the following code for an example of how I achieved this:

   1. <template id="clean_script_footer" inherit_id="website.layout" name="Clean scripts">

          <xpath expr="//footer[last()]" position="after">

              <!-- Custom Footer Scripts to be added at the bottom of the page -->

                  <script src="/theme_custom/static/js/custom.js"></script>

          </xpath>

      </template>

3. Be sure to use XHTML not HTML in all of these xml files. If you are unsure of how to write valid XHTML simply run your HTML through a converter. I used the following online converter - http://www.csgnetwork.com/cvthtml2xhtml.html

4. You'll need to uninstall your theme, update your modules list, and then reinstall to see the changes. You will need to do this with any changes you make to your theme files if you would like to see/test the changes. I had issues with my own theme's jquery javascript files conflicting with Odoo's own. you may find that you run into issues here. If you do try removing your own jquery library first and see if this helps.

Adding your own custom snippets:

1. open the following file and locate the opening <template> and <xpath> tags - /opt/odoo/custom/addons/theme_custom/views/snippets.xml - the code you're looking for is as follows:

       <template id="theme_clean.snippets" inherit_id="website.snippets" name="Clean Theme snippets">
         <xpath expr="//ul[@class='nav navbar-nav nav-tabs']" position="inside">
           <li>
             <a href="#snippet_clean" data-toggle="tab">Clean</a>
           </li>
         </xpath>
         <xpath expr="//div[@class='tab-content']" position="inside">
           <div id="snippet_clean" class="tab-pane fade">
             <!-- Typo Showcase -->

2. The comment <!-- Typo Showcase --> is where your snippet begins. Insert your snippet before <!-- Typo Showcase --> to add extra snippets. The basic structure of a snippet can be seen as follows:
   <!--My Custom Theme Snippet -->
   <div>
   <div class="oe_snippet_thumbnail">
                   <img src="/theme_porto/static/img/blocks/block_banner.png" class="oe_snippet_thumbnail_img" alt="" />
                   <span class="oe_snippet_thumbnail_title">My Custom Theme Snippet Label</span>
               </div>
                   <section class="oe_snippet_body mt0 mb32 fw_categories">                                    
                   
   <p>Here's an example paragraph snippet. Insert what you like here, but make sure it is valid XHTML or you will run into problems.</p>
                           
               
                   </section></div>
   <!--/My Custom Theme Snippet -->

   1. You simply need to insert your custom XHTML snippet in between the <section></section> tags. Be sure to use modular snippets that can be used as building blocks and placed anywhere on any page.

3. Be sure to use XHTML not HTML in all of these xml files. If you are unsure of how to write valid XHTML simply run your HTML through a converter. I used the following online converter - http://www.csgnetwork.com/cvthtml2xhtml.html

4. You'll need to uninstall your theme, update your modules list, and then reinstall to see the changes. You will need to do this with any changes you make to your theme files if you would like to see/test the changes.

5. You can add any extra images you require for your snippets in the /opt/odoo/custom/addons/theme_custom/static/img/ directory. Make sure you reference the image path correctly in your snippet (eg. <img src="/theme_custom/static/img/example.jpg" />).

This is simply how I have managed to create my own custom theme using theme_clean as a framework. There are probably better ways to do this, and I welcome any comments or suggestions on improving the process. I hope this helps get you started on your own custom theme development in Odoo CMS / Website builder.