If you have just conf champs, I could see a scenario where a 4-loss team makes it. Examples of conf champs with lots of losses:
3-loss tu beat #2 Neb in 1996
2000 b10 champs - 3way tie 9-3, 8-4, 8-4
1990 b10 champs - 4way tie (all 6-2): 8-4, 8-4, 9-3, 8-3-1
...
Once you make it so you have to be a conf champ, you are opening the way for a "crap" team to get in if any two conferences are down in the same year or you just have a couple upsets in CG. This is of course assuming the only conference playing for the title are SEC, B12, B10, ACC, + P10.