They should bring in Les Miles for a couple years. Get Tee Martin to be the OC/coach in waiting. Let Miles groom him for a couple years then hand over the keys.
Could potentially do something similar. Bring in Tee as head coach and Fulmer to handle a lot of the "front office" stuff while he learns. With that said, I'm not for bringing in Tee Martin. Sumlin would be good. And I can't believe I'm even saying this but at this point I'd prefer Kiffin over anyone else.