I think he chose this for 2 reasons 1) to think it's fashionable 2) it's the only one that fits him. Designers don't really like Kanye West (shocker!) so he rarely has custom made designer pieces (Although Decarnin of Balmain will design his tour outfits, why not go for Balmain womenswear? They're GORGEOUS! ) So he's/she's wearing Celine Spring 2011 dress (YES DRESS!) , Balmain jeans, and Lanvin sneakers.