The generic map definition already exists, if you look in ecu_defs.xml, WRXBASE has all of the tables and each revision simply adds the storage addresses to that.
The Honda guys on pgmfi.org have been doing this for years, and yeah, they have their revisions narrowed down to the point where they almost all use the same image (easier on old OBD-I and earlier ECUs, though).
What I'd like to do is set up a wiki that has all the latest ECU images for each ECU version so only those would need data offsets, like you said. This could also be used to keep the definition file updated and organized. When I get some time I'll see about setting up the wiki, or maybe Scoobypedia ( www.scoobypedia.co.uk
) would be a better place for it.. Either way, I'm too busy between work, autox and Enginuity to do it right now, but it shouldn't be too long.