You can scratch Mitt Romney off that list. His membership in the Mormon church will be a big issue. The Mormon leaders in Salt Lake would probably rather have him stay low-key so that the content of his temple oaths of loyalty to his church won't be widely discussed and so that the historical inconsistencies brewing for the Mormon church could be kept out of the limelight.
Thus for the public image of the Mormon church I think that Mitt Romney will confine his political ambitions to statewide races in Mass. and possibly Cabinet appointments in Republican administrations.
Agreed, no mormon could win the high office. The resentmen from the other denominations is too strong. Some churches even teach that mormonism is a cult.