All of this talk of how a playoff should be run..... the answer is already on display. What was once D1AA, and is now the FCS, has a playoff system that runs beautifully. The problem is the money tied to the longstanding bowl games. The NCAA can cry about its student-athletes having to play too many games, missing school, whatever.... but they already do it at the levels below FBS. (And I won't even go into the whole basketball side for missing school and too many games.)
You get a true playoff. Each game is hosted by the higher seed, on campus. Conference champs are in, and there are at large bids to be had. But again, too damn much money wrapped up in this bowl system to ever see anything like that develop for FBS. Our best hope is that a hybrid like some of what you guys have described happens with at least 8 teams.