Les Miles, maybe.
James Franklin, no chance.
My votes would be (in this order):
(1) Will Muschamp
(2) Kevin Sumlin
(3) Gus Malzahn
(4) Les Miles
Those are the only four that I could see going.
Muschamp actually seems more like an NFL guy. I could definitely see him there if he ever got the itch and an NFL team wanted him. He was DC with the Dolphins for a year and he's only 41 years old.
I don't think Malzahn would go, because he'd probably have to go back to being an OC. Maybe if he fares poorly in Auburn, he might go on to the NFL as an OC.
I could see Sumlin or Miles in the NFL, but I think both are probably more suited to the college game. Miles is also 59 years old, so if he doesn't go in the next few years, he's probably never going.
Saban's not going back and neither is Spurrier. Bilemma and Butch Jones are both college guys. Can't see Richt bolting for the NFL, either. None of the other coaches would even be in the running for an NFL HC job. (Though, maybe Freeze could be if he builds a reputation in the SEC.)