In my playoff system, the division winners from each conference get in the playoff. I'd merge/add/subtract schools so that every conference has 12 schools. Iowa State to the Big Ten (renamed the Big North), Boise State and Utah to PAC-10 (renamed PAC-12), Army, Navy, Notre Dame and Temple to the Big East, Colorado State to Big 12, which leaves 24 schools in the Sun Belt, Mountain West and WAC to figure out a way to make two conferences of 12 schools each. I would much prefer Notre Dame in the Big North but they'd balk at going to a conference where they could finish in the bottom perennially. So they'd join the Big East. TCU would probably balk at joining the Big 12 since they dominate the Mountain West. Same with possibly desiring Cincinnati in the Big North since they are dominating the Big East currently.
That's 10 conferences so that's 20 playoff spots. Just need 4 at large bids, most likely 3rd place schools from Big 12, SEC, Big North and PAC-10. But perhaps a formula could be developed so that when one of those conferences slips up, they lose a spot the following year (like how UEFA determines CL spots). 24 team playoff.
Scrap the conference championship games. However, the system could take the top 6 rated conferences and give them 12 spots, while the bottom four rated conferences hold a championship to get 4 spots. 16 team playoff.