Sarah Palin making an endorsement all depends on her popularity and influence at the time. Even if he's someone who meets Palin's criteria, her endorsement could potentially hurt his campaign based on her public perception. He may not even want it. If it's Perry or Romney...forget it; I'm sure she will not endorse them. If I had to make a prediction, I would bet that Palin doesn't endorse anyone in this cycle. This election is too volatile to take risks.
However, if it looks like Palin supporters are so disenchanted by next year that they aren't going to the voting booth, then I think she'll come out and tell us to vote Republican, even if it's Romney or Perry. She loves the country too much to see Obama win (again) due to apathetic voters.