He's wearing 2 different pairs of sunglasses in the Stronger video right? check out around the 1:54 mark and look out for these:

These are the signature series sunglasses that Jeremy Scott designed for the summer 2006 Linda Farrow Vintage eyewear collection. They were available for a while at Colette in Paris for €225, but its doubtful you can find them anymore. Kanye's got a thing for unique frames, and these are pretty bold. But he's equally adept at picking eyewear that's hard to come by these days.
Update:
Look what Mr. West is wearing in the Itunes photo for his new album. These sunglasses are getting even more publicity.

Kanye and his entourage showin’ the shades ‘round town in London.
Princes William and Harry would love to get their hands on these.