Someone posted up this idea as a possibility, I thought it would be interesting;
Vince puts him in the Rumble match as a way of forcing him to retire, saying that if he doesn't win then he's gone. Somehow Ric beats the odds and wins the whole thing, earning himself a WrestleMania title shot against Orton. WrestleMania rolls around, Flair beats Orton and wins the belt. It's shortlived, because the Money in the Bank winner (no idea who that could be) cashes in his shot and beats Flair for the belt straight after the match. Big heel heat for the MITB winner, Flair gets one last (short) reign and bows out on the grandest stage of them all.