I'm by no means an expert or even an amateur on this, but perhaps getting an attention-seeker (at least those who seek positive attention) into something where he gets the attention he needs will help, even if you have to make a deal with him that you'll allow him this alternative method of getting attention as long as he behaves in the classroom. (This is assuming he will like the alternative method.)

I'm thinking of things like drama class (not necessarily at school--the community theater would work great), doing stand-up comedy, singing or playing music, or performing in some other way.