#2 is the plan we've discussed here at OpenACS for the future. We haven't included address book in our upcoming OpenACS 4.5 release because the need to redo it seems so great that we didn't really want to start supporting it and no one really wanted to port it to PostgreSQL.
If you're interested in discussing possible design ideas with folks around here, you might want to start a thread on address book datamodel design issues over in our 4.x Design forum.
And if you're later interested on working on this as part of our team we're always open to incorporating new talent into our project!
