If UTx or KU desire, they can certainly buy out one of their out of conference nobodies and play aTm or UMo, respectively, if they desire. Also I bet that for example UWVa or TCU would be happy to schedule it so they could play Pitt and SMU, respectively, that last weekend too.
I know that highly desired at University of Northern Illinois game is tough to give up for 2012, but I bet there is a buyout in the contract. So if KU want to play UMo, they can easily do so.
Hard to see how. Missouri already has three out of conference games scheduled. Add six games against their fellow division members and three against teams from the other division and that's 12 games. So I think I'll get a bigger kick out of watching Missouri lose to their SEC compatriots than I will watching them play Kansas.
Besides, Mizzou walked away from the rivalry. The end of the Border War is on them. No use in pretending otherwise.