I would install Nolan as the interim HC on Monday and allow him to interview for the permanent position at the end of the year.
Cowher's dream job was supposedly Carolina... now would be his best chance with Fox's team imploding. Maybe he's changed his mind since those "Cowher to Carolina" rumors were so rampant, IDK.
I would be fine with Gruden. He was highly regarded as an OC in Philadelphia before going to the Raiders... and while people claim he won a Super Bowl with Dungy's Tampa Bay team the fact is that his opponent in that Super Bowl was the Raiders team he built in Oakland--in spite of the Al Davis interference.
Rob Ryan would be an interesting choice what with his brother's team one of our most despised division rivals. Still, he's done a very good job with the defense in Cleveland and players have responded with great loyalty to both his father and brother Rex. The downside with him is similar to that of his father and brother... the "loose cannon" syndrome. One minute you think he's turning your team around, and the next he's caught in some PR nightmares of his own making. Dancing with the devil here, but the payoff could be pretty nice.
I might be inclined to give Leslie Frazier a call if the Vikings don't put him in as a replacement for Childress. He interviewed with us before and it it was said he was very impressive.
Unsure about Dungy. Is he hungry to come back to coaching? He built a good team in Tampa that couldn't get over the hump and had Peyton in Indy. Would his rep be considered so highly if the Colts had one of our throwaway QBs from the mid-2000s instead? Not to mention Polian destroying the rest of the league in the draft year after year is why I'm not sure about him--he did get some awfully good players to work with.
I'm staying away from college coaches. Too much culture shock between how to motivate a 19 year old poor kid whom you can bench vs a guy making $19mil a year whom you can't.
There could be some coordinators I'm missing who are worthy candidates, but these are the main guys that would be on my short list.