KC Cowboy
Four-Star Recruit
Princton won 8 championships in 15 years back in the 1800's. Looks like Harvard did back-to-backs, Penn St., Yale....etc. I think the criteria needs to be established. Technically, Miami had a 6-peat championship run 1986-1991 according to Wikipedia. Florida St. had a 3-peat in the 90's. USC had a back to back 2003, 2004.No one since 1994-95 has won back to back championships. But I'm sure there are a great number of programs that have a back to back championship on their record.
http://en.wikipedia.org/wiki/College_football_national_championships_in_NCAA_Division_I_FBS