@H2O MAN,
Being a Christian, and living in Utah, gives me a little insight into how that actually plays out.
First though, the majority of Christians would vote Republican almost solely because of the abortion and gay-rights issues. Romney has only ever been wishy-washy on abortion, claiming in 05 that he's pro-life, but that he believes that the states should be allowed to determine their own abortion laws. His approach has always been 'I will not force my beliefs on others on that matter.' Which is precisely the opposite of what the evangelical voters want to hear.
Romney supports domestic partnership benefits (at the state level, of course, because why put your neck out). He has been quoted "We must make equality for gays and lesbians a mainstream concern."
So when you look at what Obama has done in these two categories (which, I believe, is nothing) and you look at what Romney's standpoint on both is, I can't see a compelling reason for the evangelicals to be jumping on the Romney bandwagon.
Now, as for his being a mormon. . . .
Evangelicals have a HARD time with the LDS church. Primarily because, when Joseph Smith first prayed to God and asked what religion he should follow God told him that they were all basically corrupt and that he should follow none, but rather start his own.
For the first decades of the Mormon faith they did everything they could to set themselves apart from Christianity. Their theology is strained past the point of credulity, and only recently did they discover that they can be taken more seriously by including the name Jesus in their official church title (Church of Jesus Christ of Latter Day Saints) but they can also steal more Evangelical converts by claiming to also be Christian and by having 'the rest of the story'.
So, Mormons now refer to themselves as 'Christians'. However, because of the shattered theology that they still cling too, this means that they're also the only 'true' Christians. You can imagine the evangelical reaction to that notion.
Bottom line is, there is a fairly large and very obvious rift between the two religious institutions that I don't think the hatred of one candidate over another will necessarily bridge.
But since you brought up proof, got any stats on your claim?