Your wish is my command!
I present to you...The BCS!
No matter how you try to twist it, it's not a playoff. Sorry.
And no, I'm not joking. The procedure is exactly the same as the other NCAA sports, except for the size of the bracket.
You understand that it's only a bracket if the winner of one game advances to play the winner of another, right? The problem with college football and using something like the BCS to determine who deserves to be in the championship is that the top 8 or so teams usually don't play each other during the season so it's hard to gauge merit in terms of putting teams at specific ranks. For that reason alone there's far too much subjectivity not to have a real playoff system.
And frankly, I'll take a one-round playoff any day over the possibility of having a #8 team winning the National Championship.
A playoff having the number 8 team winning the championship proves that the previous ranking was inaccurate and that the team previously ranked number 8 actually is the best team in the country. It also gives the opportunity of teams who don't have the hardest strength of schedule in the world (Boise St.) to prove their worth.