Clemson has looked meh, but their "C" game is likely good enough to get them wins against the rest of their slate. I agree with the sentiment above that they are likely in the PO but not the champ again.
Bama- top ranked, controls its destiny, has the cache to get in with an "L," has three significant opponents in LSU, Auburn, UGA (presumably).
tOSU- also undefeated and in control of its destiny. Not all cupcakes, though, and mediocre teams sometimes upset strong rivals.
OU- is in if they run the table. I don't think that will happen. Would be a strong contender if they split with us in the order they did last year.
LSU/Auburn- control their destiny in that if either somehow ran the table, they get the spot reserved for Bama. LSU has a small chance to do this, Auburn only former Heisman QB-sized chance. SEC's best chance for 2 slots is for one of these to go, along with a 1-loss Bama who almost beat them.
UGA- a CCG loss would be too late to redeem, even if the rest of their resume is in order. Their best chance in that case would be if the B12 and B10 champs had 2 losses each.
ND- will be near the front of the line of 1-loss teams if they play well. Close loss on the road to UGA can be spun different directions depending on who is still playing musical chairs come December.
PSU/Wisc- probably not getting in without beating tOSU. If somehow PSU beat the nuts to win the East, that could set up a UT-OU-Tech 08 between Wiscy, PSU, and tOSU. Therefore a very slim chance for Wisc to lose to the couch burners but still advance as a 1-loss conference champion.
Pac- just no. Unless Washington starts disintegrating opponents with laser beams after scoring touchdowns, this is too big of a clown show.
Texas- running the table would be difficult and unlikely. Not unthinkable, though, as of yet. The temptation to include a 1-loss UT on an 11-game winning streak would probably be too much for the committee. Any more losses, though, and we're out.
I don't see anyone else even mathematically alive at this point. Florida has a chance to play cockroach, though.