By your experience, could be possible turn a part of wordpress installation into a bulletin board only manipulating templates?
I explain, you have root categories: blog and forums, into those you put blog|news and forums|category1
Onto forums|category1|main forum, so you have a 3 levels tree.
Now we should be able to use blogs templates for blog category and a brand new board template for forums category.
Newer template should show posts like comments, to get the traditional view of a board post.
The newer category (forum) template should show lists of posts (threads) like traditional boards forums.
I'm explainded? Would be a more radically integration, more than bbpress or other forums...
Simply could be needed only the ability to use 2 or more themes into one installation.