Here is a good article about Frost and the general coaching carousel for 2018.
https://sports.yahoo.com/college-footballs-coaching-carousel-will-scott-frost-2018-191153413.html
One thing we should all consider with Frost's short tenure as a HC is that others in his boat are not necessarily lighting it up this year after making a move to a P5 team. First, PJ Fleck has Minnesota playing about the same and potentially a bit worse than the last couple years of that program. Also, Tom Herman has taken over a Texas team with better than average talent and has them 3-4 currently. Both of these guys took over programs that had been in the middle of the pack (similar to Nebraska) but are not having an immediate impact on the team. This is different than what we saw from Urban Meyer took over at Florida and, while the record in the first season was the same, Florida was playing much better ball than when Zook was there, and in Meyer's 2nd year they won the National Championship. Harbaugh also had an immediate impact at Michigan in just his first year there, and continues to have them performing well, but Harbaugh was also a much more seasoned coach.
My top choices would still be luring Petersen away from Washington or Whittingham from Utah, but I understand they are locked in lengthy contracts and would be a stretch. Fuente also has a recent contract extension at Va Tech. I am seeing Greg Schiano's name come up a lot too and he did improve the Rutgers program when he took over and is doing a nice job as OSU DC.