Any particular reason why it needs to be wireless? The "best" gaming headsets (Tritton AX Pros, TB PX21s, Astro A40s etc) are all wired. On top of that, with a wireless set you have to deal with a heavy headset due to batteries, and when you're gaming a heavy headset is far from ideal.
Cord length isn't a problem with top-end wired sets either, if that's the main reason you want a wireless one. I have a set of AX Pros, and apart from it being a mess of wires (the Dolby decoder box has four wires of various uses coming out of it), I don't mind that it's not wireless. The headset cord is looooooooong, too.