The plan pushed a few months ago by the TV side was like this for the 14 team playoff and it apparently got some decent traction.
Basically, it is a 14 team model with 2 byes and the SEC and B1G each get 4 automatic spots, ACC and Big 12 will each get 2 automatic spots.
Play in games would look like...
-SEC championship would be 1 vs. 2 (so this past season as example, Texas vs. UGA). Winner gets the bye, loser still gets a guaranteed spot.
-Then 3 vs. 6 (Tennessee vs. Ole Miss) and 4 vs. 5 (Alabama vs. LSU) in play in games (on campus) for the other 2 guaranteed spots.
-B1G championship would be 1 vs. 2 (Oregon v. Indiana). Winner gets the bye, loser still gets a guaranteed spot.
-Then 3 vs. 6 (Penn State vs. Iowa) and 4 vs. 5 (Ohio State vs. Illinois) in play in games (on campus) for the other 2 guaranteed spots.
-ACC and Big 12 would either go with 1 vs. 2 in their championship game with winner getting the higher seed, or have 1 vs. 4 and 2 vs. 3 playoff style games with each winner getting the guaranteed spots.
-There would be 2 at large spots left... likely one guaranteed for the highest ranked group of 5 team if they choose to allow them a seat at the table still. The other spot would go to Notre Dame if they are ranked high enough, or it to the best overall team that lost in the conference rounds.
You'd have 2 byes and reseed after the first round. The TV folks want it and when there is more money to be made (because of more games), that is usually where things ends up.
Another possibility considered on the matchups would be to go by the CFP rankings instead of the conference rankings for the teams that are not 1 and 2 in the league and competing for the actual championship. That could reward teams who play tougher schedules, have better resumes, etc. over teams that played well in conference but maybe aren't as good overall as other teams.