Could Floyd end his career as the best ever?

[Kev]

If Floyd beats Shane Mosley, and then went on to beat Manny Pacquaio where would he rank on an all time scale?

I mean to be 42-0 against such high quality opposition, with no losses, never put down, never hurt, it would be an awesome acomplishment.

Also for me the quality of opposition argument couldn't really be used against him as who else from 125-147 should he have fought?

It would be an amazing legacy in my mind. I mean no other fighter would have come close to going through an entire career, against such opposition, without ever losing a fight.

If you don't think this is the case, who would he have to fight in order to get up there, or is it simply impossible no matter what he does?