Have you seen:

https://apps.openerp.com/apps/modules/8.0/product_sequence/

https://apps.openerp.com/apps/modules/8.0/mrp_bom_state/ 

MRP - BoM version

This module provides a state in the LdM whether to allow their use in manufacturing, to do the following states are defined:

Draft: The form will be available for data entry, and may move to "active" state.

Active: You can modify all of the form fields except for the fields: routing, BoM lines, and the new field Active, for false default when you create a new BoM. The "active" state may be passed back to state "draft", if we mark the new field "Allow re-edit the BoM list", this new field is defined in Configuration > Configuration > Manufacturing. The active state may move to state "Historical".

Historical: This is the last state of the LdM, you can not change any field on the form.

When the MRP BoM list is put to active, a record of who has activated, and when will include in chatter/log. It also adds a constraint for the sequence field to be unique.

New version : By clicking the button version, current BOM is moved to historical state, and a new BOM is creating based on this but with version number +1 and changing state to draft

Here is a more detailed explanation of the issue.

The source of my problem is to import different BOMs for different product variants. For example:
- I have a widget that can be red or blue as well as square or round.

Depending on what the customer selects, we will have to use a round or square case and red or blue ink.
To the best of my knowledge, the way to solve this is to import 4 BOMs:
A. Red ink and Square Box plus standard components
B. Red ink and Round Box plus standard components
C. Blue ink and Square Box plus standard components
D. Blue ink and Round Box plus standard components

And to import these different BOMs I need different "internal references". Someting like:
A. WDG-RD-SQB
B. WDG-RD-RDB
C. WDG-BL-SQB
D. WDG-BL-RDB

For 2 variants this is manageable to create these manually, however, for 100+ variations, this becomes a pain.
In OpenERP7 it was easy to create these codes. Now this functionality is missing. I would be also ok if someone would help determine how to import different recipes based on variants. :)

Did that help clarify the question?