My problem with Romney (speaking as an Independent, Fundamental, KJV-Only Baptist) is not that he is Mormon, but that he is untrustworthy on the moral and social issues like abortion and guns which are very, very important.
I agree with Titus. It is not his religion that precludes him.
BTW, Mormonism is NOT another form of Christianity. Mormons do not believe in the Trinity and salvation by grace alone, the pillars of Christian doctrine like Baptist and Catholics.
Mitt Romney has been endorsed by some of the most prominent pro-life leaders in the nation. James Bopp Jr. is National Right to Life Committee's chief lawyer and he has actually joined the Romney campaign. Dr. Jack Willke is, basically, the father of the pro-life movement - he helped found the National Right to Life Committee (America's premiere pro-life organization) and was its founding president. He just recently endorsed Mitt Romney and said, now this is very important to consider, "Unlike other candidates who only speak to the importance of confronting the major social issues of the day, Governor Romney has a record of action in defending life. Every decision he made as Governor was on the side of life. I know he will be the strong pro-life President we need in the White House. Governor Romney is the only candidate who can lead our pro-life and pro-family conservative movement to victory in 2008."
Romney is FAR from being "untrustworthy" on issues such as abortion - and especially on the abortion issue, he can be trusted to uphold and protect life and good moral values.