I've come up with a ranking system for college football similar to the RPI system for college basketball. There are a few slight modifications though. I've scaled wins and losses based on margin of victory, opponent strength, and home field advantage. I used this adjust winning percentage as a portion of each schools score. I also used opponents' winning percentage and opponents' opponents' winning percentage.
There are some quirks. Arkansas is seemingly ranked way to high, but they did play one of the hardest schedules, played good teams closely, and blew out most others. Some notes: margin of victory was capped at 28 points, FCS wins do not count, FCS losses are counted as two losses, and scores are normalized so that the top team has a score of one.
FBS Top 25