Looking ahead to the post Obama 2016 election, PPP Polling, which although Democratic party aligned has had a remarkable track record, polled Iowa, the first in the nation GOP primary state.
If there was a total acceptance that not only would Mitt Romney be the 2012 nominee, but that he would defeat President Obama and then run for a second term, then such a poll would most likely not see the light of day. A poll of likely Dem candidates is a different story of course.
PPP is even dismissive it appears of Romney being in the hunt for another shot at the nomination if he loses to Obama in 2012 "Maybe Mitt Romney will be the GOP candidate in 2016" the state and then they go on to do a poll omitting him.
Of the candidates polled Sarah Palin has the highest favorability rating amongst GOP voters in Iowa at a remarkable 70%. As far as voting intentions at this point are concerned, Palin polls in equal third place (two are tied for first place.)
It is not surprising that Huckabee and Santorum are tied for first as both campaigned hard in Iowa and won the state in their primary runs. I would be very surprised if Huckabee declared for the nomination in 2016, and would be amazed that if Palin did declare, and worked the state, if she didn't win Iowa or finish a close second.