A nice DLC idea, would be to have a whole city based off of Snow Elves, before they turned to falmers, or at least a new Crown Store Motif based off of Falmer Armor.
Snow Elves are already Falmer by the time period of this game but they could always pull a Skyrim and have you find a secret sanctuary where a few are alive or something.
I don't always drink Skooma, but when I do I go to the Southwall Corner Club. May you walk on warm sands my friends.