As posted in the Skyrim Nexus's news section, a forum user recently posted about a number of new animations included in the latest patch. These animations are not actively used by any of the new features, so they must be part of a planned DLC or updte. Whether crossbows are simply going to be released in a future update like the killcams and Kinect dupport, we do not know. However, crossbows are quite a major addition. Not only are they an entire new type of item, but they most likely mean the addition of new crossbow-related perks, enchantments, and quests. Such an inclusion seems far too major for an update, and would suit a DLC far better.
Furthermore, there is evidence that the first DLC will be about the Snow Elves (Falmer). Why? Because there is a new group of animations that include "DLC01" in the title that are for "Snow Elves". Put two and two together, and the best guess is that the first DLC will be about the Falmer. I always thought that Blackreach would be featured prominently in their DLC, and it appears that such a guess may turn out to be truth. In addition, there are also new animations with "DLC01" in the title that seem to be for vampire feeding. Most likely, these animations are for the vampire feeding that we saw in the Skyrim Game Jam video.
As far as the animations that are listed last in the Nexus post go, my guess is that they are facial or body-movement animations for a new character or character type. The filenames seem to indicate that they are to be used for various emotional moods. If so, then these animations could be for a new Falmer follower or character.
Theories? Arguments? Nerd ravings? Comment below.