Every election only has one losing ticket.
People who did not win previous nominations often go on to win their party’s nomination and the White House (Reagan, as an example.)
But you will be very hard pressed to find someone who was on a losing ticket who went on to win the presidential election later. Nixon and FDR. But that’s it.
No one has ever gone on to defeat the candidate they lost to in the previous election, though several have tried. Mondale, Stevenson, and Dewey all ran against candidates they had lost to 4 years earlier, and not surprisingly, not one of them produced a reversal of America’s judgement.
A Palin/0bama rematch is guaranteed to meet the same fate.
However it is odd that if you are so sure of such a result that you are spending time denigrating Palin.
Dewey ran against FDR in 1944, and Truman in 1948.