Andy Peatling, Automattic employee and Buddypress team lead, has announced that the beta will be released on Dec 15 and the full release is targeted around Christmas.
Check it out to see if it would suit your vB community, don't forget that it also has the full power of WordPress MU (give WordPress blogs to thousands of your users, all from one installation) under the hood:
BuddyPress Website
BuddyPress Demo