I think some of the guys that have already been mentioned would be good choices - Winky or the winner of B-Hop/Calzaghe.
The winner of the Miranda/Abraham fight would be another possibility.
I think I'd like to see Calzaghe fight Pavlik. I know a lot of people disagree, but I don't think Calzaghe has done enough to be considered an elite fighter, even if he wins tomorrow. Assuming he beats B-Hop, what has he done in his career? He beat an overrated Lacy, an aging Hopkins, a ton of European nobodies, and Mikael Kessler. I'd love to see him get his ass handed to him, and Pavlik could be the man to do it. Not many people in that division hit as hard as Pavlik, and Cal's been dropped before.