Clarett and Phillips had much better careers than Vick though - especially Phillips. Clarett only played one year but was seen as the key player in OSU's national championship run. They were also running backs which is much easier to transfer to the NFL than an QB.
I think he will be a free agent signing - I just don't think that anyone will want to have him listed as one of their draft picks. With a free agent signing, the press coverage will be much less - especially when he gets cut.
He really needs to go to NFL Europe and play a couple of more years.
If he really wants to get some experience he should sign in the arena league, a much faster game. He'll learn to make fast reads and decisions. I don't see guys getting better playing against other players who aren't NFL caliber in a slower game.
I still think someone (the Raiders) will take a chance on him late, Clarett and Phillips were better collegians, but they don't have Ron Mexico as a big brother either. The draft is all about what might be.