The first option should always be to offer a blank check to Nick Saban.
If you can not get Saban you start considering what your options are.
The first call you should make should be to Dan Reeves. Even if he turns the job down, you should ask for his opinion.
After that dial up Marty and see if he is interested in having the team play some MartyBall. If you still do not have a coach after that, you are pretty much screwed. At that point, calling Tom Izzo and seeing what he thinks about changing sports might be your best bet. It would be even better if you could get Robert Montgomery Knight to put the fishing pole down for a few years.