Are we 100% positive this is legit footage? Something just seems "off" about it to me, not sure why - some of the graphics and design look different from official videos we've seen in the past... also I couldn't see any mountains in the background whatsoever, but I'll take another look. Not sure what other game it would be though, so I'm inclined to believe its real.
EDIT: Thing that strikes me most is how linear it is - TES games are designed so that the player can travel anywhere at anytime. Todd even said we could climb any mountain if we wished. I'm beginning to get even more doubtful now.
I was expecting it to be rather linear - but I agree - there's still something "off" about it. It looks like it could be Skyrim (a more foresty region)... but at the same time, it could be something else.