You are aware that Microsoft is planning to discontinue public folders natively in Exchange, I think in the next version(whatever is after Exchange 2007), right? It actually wasn't originally going to be included in Ex2007. I know that is a long way off, but if you are into planning ahead for the next revision, you may want to look into that. I believe the public folders are going to be migrated into a Sharepoint Server and Exchange Server combined setup.
Of course, it's probably been 18 - 20 months since I've looked at an Exchange roadmap, so I could be wrong(that's my disclaimer). I do admit that it would be nice to have a public folder setup, or something in Zimbra without having to do the nasty workarounds of large calendar/mailbox sharing...etc. If only there was some way to request that...hmmmm. I guess I'll have to visit bugzilla or something
