Caveats
Not sure what is going on with his legal situation, last I knew the woman that accused him never filed her suit. Obviously this has to be sorted before he could be hired.
He probably says no, but you call anyway.
That said, he's a great option that I haven't seen kicked around yet. He's not perfect obviously but KU isn't going to get a top shelf coach. You either have to go established with some baggage or young and risk the coach not being very good.
D1 Coaching career
Took West Virginia to national prominence.
Bit off a bit more than he could chew at Michigan. Rebuilt the roster after Carr retired and Brady Hoke went 11-2 with RR's players before flaming out.
Turned around Arizona from the stink of Mike Stoops. Arizona is a similar football job to Kansas. Better location and slightly better natural talent base but not by much. Had more actively good programs than the Big 12 does when he was succeeding there. Last few years there were mostly average but competing with very good programs in Washington, Stanford, USC etc...
Exhibit A for coaching ability: Khalil Tate playing for RR vs playing for Kevin Sumlin.