An all-Mormon ticket? No way. If Romney made any promises, it wouldn’t have been the VP short list. From Huntsman’s perspective, a cabinet office might be more attractive, particularly if he has delusions of doing better in a future Presidential race.
The only post I see Huntsman getting is Sec. State. He does have some international chops, which is one thing that made him attractive to some people.
There’s no way Mitt would put him in as VP. It would be LDSuicide.