I'd say we do have an OT forum. It's called the "internet".
I'd just hate to see flamers and trolls turn this into just another BB website, but perhaps there could be a section called 'junk mail' or something, and the moderators could move all off-topic posts in threads to it, in order to keep threads on topic. I just wouldn't call it something like 'trash can' as that would probably be inviting trashy posts.
There is a christian BB based website (ABCbodybuilding.com) that has strict regulations to posts, and they will DELETE trolling and flamers, but they also seem to have a successful miscellaneous forum and even a spiritual forum. But it's done by strict moderation, no attacking allowed.