As promised (or threatened), the record driver refactoring project is now complete.
As of r2231, VUFIND-118 has been resolved and the record_drivers branch has been merged into the trunk. It should now be much easier to add support for non-MARC record formats. This refactoring also served as an excuse to do various bits of cleanup work -- some potentially reusable logic that was previously embedded in various Record module actions has been moved to utility classes in the sys folder (review/excerpt loading, citation building, OCLC API calls).
This is a big change, and I apologize if I've ruined anybody's day by forcing complicated reconciliation to get your local customizations working with the new setup. I'll be happy to answer any questions if you run into trouble. I'm about to start on some reconciliation work myself to get Villanova's customizations lined up with the new trunk code, so I'll be able to advise from experience shortly!