I don’t understand your logic. BuddyPress is a plugin for WPMU, which is a multi-blog version of WordPress. bbPress is a forum program. Not a plugin for anything, just a standalone forum.
Merging BuddyPress and bbPress would be like merging a car company and a grocery store. You can drive a car to a grocery store and carry groceries in it, but integration is as close as you can get to merging them.
Besides, no other major forum software (phpBB, IPB, VBulletin, SMF, etc) have a social network built in or are a plugin for a blogging program.