Seems there are no really big names out there. The only name that seems to be coming to my mind is Tressel but I'm not sure if he is edible to coach or not.
I think he has another 2 years to go. The most frequently mentioned names I have seen are James Franklin at Vandy, Art Briles at Baylor, and Mike Gundy at Okie State. You could probably throw Gus Malzahn in there despite his recent contract upgrade, and no major coaching search would be complete without a Jon Gruden rumor.