The two hottest names, according to a friend of mine who is obsessed with Iowa State athletics, are Turner Gill and Gary Patterson.
Gill might be a pipe dream in my opinion. If he keeps the train running for another year or two in Buffalo, he might be able to land a really big opening after 2009 or 2010. If he takes the Iowa State job now and struggles with it, the doors to bigger jobs might be closed that would otherwise stay open if he continues to have solid teams at Buffalo. Then again, Chizik was 5-19 at Iowa State and now he's coaching Auburn, so who knows?
Apparently, Patterson's wife is an Ames native, so that's fueling some of the fire for this rumor. My thought on Patterson is, TCU isn't a terrible gig. Great natural recruiting base, and recent success probably allows him to at least get in the living room with guys who might end up at Oklahoma, Texas, etc. He gets national recognition for the job even though he's not in a major conference, and he gets crazy loads of love from the locals and alums. I have to think if Patterson had his eyes on a BCS job, other (better) opportunities have presented themselves, and likely will again down the road.
I personally think Mason would be a solid hire for Iowa State considering the current level of the program, Mason's familiarity with the recruiting territories around the Midwest, and his proven track record of taking teams that are typically 2-3 wins/season and building them into 6-7 wins/season with the occasional sparkle of a 9-3 mixed in. I don't think Mason is the guy to get ISU to a BCS game soon, but he might be the guy to get them into the bowl schedule on a regular basis. The one question would be recruiting head-to-head with other Big XII and Big X teams. He gets the most out of some unheralded guys, but would he be able to bring in the type of talent ISU needs to compete in the Big XII?
Other names this friend has thrown out there: Troy Calhoun (Air Force), Pat Hill (Fresno State), Todd Graham (Tulsa) and Kevin Sumlin (Rice). He seems to think there's a decent chance of landing Pat Hill, who responded "no comment" the other day when asked if he'd been contacted by the folks in Ames. Hill would be a huge get on par with Gill or Patterson IMHO. Calhoun is another guy my friend is really high on right now. He also notes that Sumlin, though not holding a great record at Rice, has done a lot with a little, which is something the ISU job will likely require.
On the Jay Norvell thing, he really hates that idea. I bet a lot of people in Ames will be reluctant to hire a coordinator from a top dog Big XII team after feeling snakebitten by the Chizik thing.