I came across this slightly altered version of it yesterday when it was tweeted out by a guy in Notre Dame's sports information office. Which, according to this NY Times article, is somewhat true, "Notre Dame has a highly nationalized fan base." (if interested there are some interesting stats in that article, including "Most popular college football teams in the Omaha TV market".
Anyways, the ND map made me want to go find the original and here it is. Blow it up and you can see all the smaller teams. I'm sure it isn't perfect, but it is a very fun infographic. (Sorry about your small territorial representation, Cyclones. It is the Hawkeye State, after all.)