I saw the Trailer when it came out, and I have since tried to keep an eye out for the soundtrack for this DLC.
I have a friend on XBox, and he said that much of the music came from Morrowind, many with deviations from it.

But what I am most interested in is the... darker version of the Skyrim main theme found in the trailer. Does anyone know if Bethesda has the full track released, if not whether or not they intend to release it? Because that version of the Dragonborn track sounds beyond awesome, and I would love to hear the full version at some point. Can anyone point me to it, if it exists?