WP as a board, only editing templates

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.