Well, here's the thing: we are probably not getting hair physics.
HOWEVER -- if Bethesda wanted to, it'd take maybe a day for an experienced modeler/animator to add hair bones and have the bones animated along with characters spinal cord. Hell, even I know how to weight animation bones in Blender. It'd be fast, simple, and Skyrim would be able to have long hairstyles without massive clipping issues.
Please, Bethesda? I want a long ponytail.
EDIT: Oh snap, just realized vsions posted. Now I feel bad for asking for things, especially as some of my comment above might be seen as belittling the work you do . . . I'll leave it for posterity though. You've done an excellent job from what I've seen thus far; thank you for communicating so much on the forums!
DOUBLE EDIT: VV Dang, I was too slow. I totally feel like a jerk now. Things are probably different between Skyrim and just modding Oblivion.