How long before Mayweather is stripped of his belt by the WBC?

[Lance Uppercut]

Hatton was the #1 contender for his welterweight belt when they fought for that last December.

He won't fight a natural welter, it ain't his thing

Exactly. After Hatton vs Mayweather was signed, the WBC announced that Hatton was the #1 Mandatory Challenger for the WBC Welterweight Title.

Thus, Mayweathers next mandatory will not be due until December 2008, and after that he could always ask for an extension, which are frequently granted for their biggest money makers.