Well mosley didn't suffer hist first loss till he was what 35-0 and 32 years old or something...but well then he bumped into vernon forrest, I don't think many people fancied a vernon win, so who knows just because it doesn't seem like there is anyone out there does not mean there isn't...but then again mayweather fights pretty seldom, so wouldn't surprise me if he only had a couple more fights and retired undefeated.