I'm kind of surprised how quickly people seem to be writing this off. I don't necessarily think the offers in question are good enough to pull him away, but I also don't think it's out of the question for an FBS team to offer him a HC position. And it wouldn't exactly be unheard of for him to take it. He's been a coordinator for almost 15 years, including three successful seasons at a BCS program. Unlike most coordinators, he now also has experience as an acting head coach at a major program, and in that time he presided over one of the most successful recent stretches for that program while navigating a very tricky situation while getting a lot of negative attention from the media due to Kills health problems. When you take into account the first-hand experience he has being around a stable staff that builds programs for a living, it's pretty obvious why a lot of teams would want him as their head coach. What he's done here has been incredibly impressive.
I certainly wouldn't go so far as to say I even think it's likely he goes after this season, but it wouldn't shock me. What would shock me if he continues performing like he has and he's still here two years from now (unless he's here with an understanding that he's something like a successor-in-waiting to Kill).