The T-Mobile bound Lumia 925 variant RM-893 has been caught getting tested on AT&T in Occasional gamer stats. Surprising, as it is a T-Mobile exclusive device.
Having a look at the specs page at Nokia Developer and at Nokia USA confirms RM-893′s compatibility with AT&T’s LTE band 17 (700).
So, it seems really possible that if it is not coming to AT&T being T-Mobile exclusive, it may still be compatible with AT&T network and users may even be able to use the AT&T’s LTE network. Seems beauty Lumia 925 and beast Nokia EOS both may be available for AT&T users.
Nokia developer link