Well, the Windows Phone site shows a green/yellow one for their picture of the 8X on AT&T, so they will probably have that one as an exclusive, with T-Mobile only getting the Blue. It's certainly possible they will both get it though, Verizon might be the only one that isn't, due to it's exclusive of black and red.
Originally Posted by Winterfang
Phones | Windows Phone (United States)
Actually it shows a black one for T-Mobile, so it's obviously not really telling us anything, they just stuck three different colors there so it would look better.