I find it hard to believe that anybody is still putting stuff on in SD these days. HD is standard, and I think it has something better than 70% saturation. It doesn't cost any more to broadcast in HD, does it? I'm not sure what the business model is for ESPN, but they must somehow get a better deal from the cable companies if they put some games on SD rather than HD. The Stanford-USC game is the one I can think of last year that was inexplicably on ESPN2 SD.
FWIW. Michigan doesn't seem inclined to get re-involved.