UNC football is not in a position to take any successful HC from schools like Clemson, FSU, VT, Miami. I'd take Dabo over any coach in the country right now, in part because Saban is much older, but as that is impossible, it doesn't matter.
Save in this sense: unless you are happy with UNC football always looking up, then you must demand a coach who can beat out the above 4 programs, as well as GT. And no UNC coach can come close to doing that halfway consistently if he cannot dominate Dook and Moo.
If we were restricted to ACC HCs, things are a bit less obvious. Petrino would put up nice offensive numbers at UNC, and when he can get a top D, his teams can win truly big. But his baggage is just too much for UNC.
Clawson is a possibility, because he knows how to rebuild and build up from what he inherits. He coached at 3 schools before Wake and won a least 1 league championship at each. Clawson at a state school might prove to be the real deal. And he is a class act.
Mendenhall has UVA turned around. He inherited a dumpster fire, and in his 2nd season has the Hoos in a bowl. He coached at BYU 11 years and never had a losing team. He had 5 teams that were double digit in Wins. His last BYU team won 9.
Nor did Mendenhall inherit a winner at BYU. The last 3 teams before Mendenhall took over were: 5-7, 4-8, 5-6.
The current coach in the ACC I would most want as UNC HC, with a caveat, is Brent Venables. The caveat being that Kevin Wilson be his OC. Yes, I would take the uncertainty of a 1st time HC, because Venables may be the best all around DC in the country, and now he knows the ACC.