Since this thread has gathered enough eyeballs I think if a group of people interested in porting phpBB then they should do it. Once the new package or modified forums are there, and the community sees that its better then it will likely be integrated into OpenACS. This situation is no different from forums and bboard. OF decided that bboards was not good enough, so they made forums. The community agrees and now forums is part of OpenACS and is used in openacs.org.
Has anybody noticed that pressing "Cancel" when you post still posts and not cancel the post. :)