I don't know that I'd be quite so quick to label reluctance to vote for a Mormon as "anti-Mormon prejudice." I think it's quite clear that most active Mormons are NOT Democrats, so that would make it hard for a Democrat to vote for a Mormon. On the other hand, some Mormon politicians have been known to be very moderate Republicans, so maybe it's wrong to think they're all right-wingers.
I think both Mitt and George Romney have had a reputation for being decent, reasonable men.
-Joe-