It would be nice to have any numeric value key-frameable, but I wouldn't hold my breath.
There is a work around for almost everything you could want to keyframe, though - use a dummy object (an empty group, for example), and use visual logic to tie it's animatable values to the things you want to animate. In this case you could do "DummyGroup.PosX" linked to "MyMaterial.Layer1.Texture.TextureCoords.Position.X"
Then you are free to animate the DummyGroup's position any way you want, and the texture coords will follow.
#XPression