Who is Left for BJ Penn to Clear Out of the UFC's 155 Pound Division?

BJ Penn (14-4-1) is one of the top Pound for Pound fighters in the world. 

He defeated the two top contenders in the UFC's Lightweight division in convincing fashion by finishing them both.   Now he has interest in fighting one man that had defeated him two years ago. 

That man is the current UFC Welterweight Champion, Georges St. Pierre (16-2-0).  Penn lost to Pierre via Split Decision back in March of 2006.  He has rebounded from that loss and another to former champion Matt Hughes by dominating No.1 contender Joe Stevenson (29-8-0) and former champion Sean Sherk (34-3-0).

 So my question is who else is there to beat to clear out the division?  Kenny Florian (9-3-0) and Roger Huerta (21-1-1) are fighting to distinguish themselves for the next title shot.  Nate Diaz (8-2-0) is making a run, so is Rich Clementi (40-12-1).  Tyson Griffin (12-1-0), Frank Edgar (8-1-0Mayard (5-0-1) are looking great.  

I don’t think any of these fighters mentioned really stand out as a potential title contender, but that has never stopped the UFC to give away title shots.  I think it would be O.K. for Penn to meet Georges St. Pierre at a catch-weight of 175 pounds for a rematch, after that they can go back to defending care of their respected belts.) and also Gray