I don't think Vernon wins, time and time again Mosley has shown himself as not a true boxer. He is a boxer puncher who does great when he can fight at his range which is close enough to throw combinations and far enough to dodge his opponents punches, the tallers guys like Vernon and Winky didn't let him find that distance and also Mosley isn't very good at going backwards, at lightweight he was so powerful he never learnt how and its definitely something you need to know how to do. Mayweather has all the things Mosley didn't, a great defense(not jut reflexes), great footwork(though he is using it less and less), much better pot shot type fighter(which is the only way a short guy can beat a tall guy from a distance), and he has a much better sixth sense than Mosley in that he knows punches are coming even when he doesn't see them. I don't think you can compare Mayweather against Dela Hoya or Hatton with Vernon because they are both faster, and have always been faster of foot than Vernon. If you say Robinson beats Mayweather thats a given because Robinson was intelligent, he threw good combinations, he threw bombs from unpredictable angles, but Vernon isn't that great, Mayweather has foughten plenty of tall guys (Corrales, N'dou, Oscar just to few) and none of them were able to take advantage of their height). A guy similar to Mayweather Roy Jones jr. showed plenty of times what speed does to height.

Plus I see Oscar beating Karmazin, I see Oscar beating FOrest if they fought... I felt Quartey beat Forest as well in a close fight... I see Mayweather being able to win this relatively weak division compared to the one he is in right now.