The truth is there aren't really any realistic elite coaches, especially on defense. Muschamp hasn't had a good defense in about 10 years so one can say his best days are behind him.
Jim Leonhard isn't coming here. Phil Parker isn't coming here. You can make the case for Heacock but I'm sure even some people here would say he's a Big 10 guy and his defenses don't work + the guy has never had a defensive player at Iowa State drafted in the NFL.
Mike Tressel and Doug Belk have limited DC experience. Schumann is big part of an elite DC but he's never been the guy so high risk high reward.
Go to the NFL and hope for a Macdonald/Michigan type of situation? Mike had zero experience as a DC so that was quite the gamble.
Point is there are some options but almost all of them have legit question marks. Few, if any, should be considered "elite." This makes Mason arguably one of the more "elite" options out there all things considered.