Andersonpowerlifting.com and liftinglarge.com are two sites I have experience with, both good sites. Elitefts makes and sells their own wraps, but I can't vouch for them.
Honestly, the main wraps I use these days are generic wraps from roguefitness.com. They have Velcro which means you can't use them for meets, but they're SO MUCH easier to use for training. I put them on fairly loose and it really helps me rep out with heavier loads.