I do believe that TCU finished ranked in 2006, and Utah finished ranked in 2009.
Also I don't know if this is the best metric to use to judge "good" wins. Ranked teams don't lose very many (0-3) for the entire season. So anytime we beat anyone in a power 5 conference, they are likely to lose at least a couple other in their conference and finished unranked. I think looking at his record versus top 25 teams when they played is a better overall metric.
I'm sure if you looked up other perceived great coaches, they would have an abysmal record versus teams that were ranked at the end of the season.