Does iOS support IEEE802.11e QOS functionality?
Certainly on the Airport range, MacBooks, and iOS devices there's no QOS, Apple doesn't support it. Not sure about the Mac Pro or Xserve.

EDIT: In response to requests for sources, it's very hard to find an official source for something that isn't implemented, but a simple google search for "does apple support qos" will result in many links to posts about someone asking the question about various Apple products, several on Apple's own support communities. Everything points to no QOS because it simply doesn't exist on Apple products.