I beleive there are a lot of people who would love to have a forum integrated with their blogs, like it's done in the ExpressionEngine or CommunityForum ('The Daily WTF' is running on, btw). that would be a perfect paid upgrade and there was already plenty of similar requests around here.
the matter is, bbPress is not even 1.0 now, for the one thing; and nobody has hacked it into MU (MultiUser) yet by a similar way Donncha did it to WP.org which resulted a WP.MU which .com is running on.
and even if anyone will ever do that, then bbPress.MU will eventually have exactly the same user experience issues as WP.MU has now i.e.: common-shared, non-editable raw .PHP themes, no user plugins, no JS and HTML forms allowed etc.
basically, bbPress is now going through the same ontogeny path WP.org has already gone. that's why Trent is right on money: it'll take rather much time while bbPress community of volunteers, which is now busy with making documentation, plugins and free themes, contributing to the support knowledge base, submitting fixes/enhancements, security patches etc, etc, etc.., accomplish all that to an acceptable level, before bbPress[MU] could be used in the commercial environment for profit.
and AbbyD is absolutely correct too: .com requests queue is indeed being filled by a huge number of so much high-priority requests that even completely borked navigation on .com blogs caused by the obtrusive usage of global tags links, or usability enhancements to this very forums theme (beneficiary for forum regulars) can't be fixed (first issue is during a year and half). despite a fact, all it takes is a 5-minutes one-liners.