Floyd Mayweather jr. vs. Shane Mosley would be a close fight as long as it's in the welterweight division. If Mosley can lure Mayweather up to 154 lbs. I'm not sure. Mosley is a slightly bigger man but at this point in their careers I think that Mayweather is faster. Other than that their overall talent level is very close. I think that Mosley goes better to the body but that Mayweather is slightly more versatile, can fight with several different styles and is at least as good on the inside. Mosley is versatile too though, and since he's moved up in weight he's done a lot more stalking and flat-footed punching. If it ever happens it will be a great fight.