I have a hard time imagining a "Massachusetts Mormon" winning any of the Bible Belt GOP nominations. Keep in mind that Iowa (and my neighboring state, Nebraska) is NOT part of the Bible Belt.
Evangelical fundamentalists are just a loud minority group here -- nowhere close to being a majority. So its not surprising that a Mormon, like Romney, might do a bit better here. Less Republicans around here think he is, literally,
"a polytheist controlled by the devil." And even taking that into account, he still won less than 25% of the vote (even with the 'party establishment' backing him).