Hello

You will have to use webkit report engine module so you can create here multiple header and use it in your report

Yes You can use webkit report engine by using this module you can create multipleple header add multiple logos etc.

In RML you can put header code direct inside the report rml file to use different headers for the reports.

Put your header context inside the <pagetemplate></pagetemplate> tags in the report rml file and add the parameter header=False to report_sxw call in the report py file.

For OpenERP 6 there is the Elico Corp module base_report_header.. Let me know, if this module works with OpenERP 7 too.