First of all I'd eliminate the Rose Bowl from the BCS.
3 BCS Bowls - Sugar, Orange, Fiesta. 2 of the 3 bowls feature the top 4 teams in the BCS standings. The Orange Bowl will feature 1 vs 4, the Fiesta Bowl 2 vs 3 (this would alternate along with the Championship Bowl game each year just as it does now) Winners play in the Sugar Bowl, or the Championship game. Championship game alternates every year (like it does now, but every 3 years) and is played 2 weeks after the 2 playoff bowls. Oh, and like the XFL, winning school gets all the money from the Championship game instead of splitting it.
At least you get a playoff system and things are decided on the field. A larger playoff format will be harder to get and would end up with more games, taking up more time. This effectively has 1 more game played 2 weeks later between 2 schools. I think this type of system could be put in place as soon as next year if they wanted.
Of course, Team #5 would feel snubbed or something..but its still better than it is now.