The scenario - Maximum carnage in the SEC (Bama, Tennessee, Georgia, Texas, Ole Miss all end with three losses). Maximum Carnage in the B1G other than an undefeated Oregon (Ohio St, PSU both take a couple of losses). Miami wins out in the ACC and no other ACC team is undefeated.
Iowa State loses Farmageddon to KState, then K State beats an undefeated BYU in the Big 12 Championship. You now have three 1-loss Big 12 teams. In that scenario, you are getting:
3 Big 12
1 G5 Champ
1 Acc Team
Notre Dame
3 SEC Teams
3 B1G Teams
Not likely, but something like that could easily happen.