[Zope-dev] UserFolder based on an RDBMS?

Hello, We're trying to convert a large site over to Zope which makes some heavy use of information stored in an RDBMS and wondered if anyone has done any work extending the BasicUserFolder/BasicUser classes so that they get their information from an RDBMS instead of Bobo? How about any pointers to code which can be used as a starting point? Another question we had was if it would be possible to extend acquisition to include properties/methods defined for the currently authenticated user? This would be useful for user preferences, etc... thanks, -jeff