I would be mildly surprised to see KU fire Gill. I can see them doing it, but the financial penalty in doing so, coupled with the stigma that would go along with how they treated Mangino, followed by how they treated Gill, would just be a huge hit in their ability to go out and hire 'the right guy'.
It's not like KU was ever a football power that's just a coach away from going back to the mountain top (i.e. Ohio State). It's a job that requires a significant time investment for a coach to be successful, and if KU is going to fire a guy two years after he won an Orange Bowl, and then they go and fire the next guy two years in on the job, well, I can't see that as a place I'd like to try and launch my career.
Missouri did it the right way. They got the guy they thought could turn around their program, and they knew where their program stood on a regional and national level. Because of that, they gave him seven years before he had that real "breakout" year, and that lead to forty wins in four years.
If KU wants to have a program that has consistent success, they will let Gill coach one more year to minimize their financial impact and give him something that resembles a fair shot, and they'll spend their efforts behind the scenes trying to identify the 'right' coach for the job. No matter what happens, they're starting over from ground zero, whether it's 2012 or 2013. There's no rush for them to make any movement unless they really feel like having 20k people in the stands vs. the 25k they're (realistically) bringing in is going to make that big of a difference in 2012.
Honestly, if I'm KU, I hold out for 2012, and then in 2013, I'm looking at Dave Doren or Larry Fedora (if he's still on the board). They need to invest in a SLTH (like Pinkel) and just give him seven years and see what happens.
