I can't imagine a circumstance where the Republican Party has the balls to deprive the plurality winner of the nomination, especially when I'm sure the media would turn it into 10X the news story necessary. People would be riled up by the media implanting the idea of some sort of injustice or false nominee that they would foam at the mouth over.
Romney currently has about 40% of the popular vote (Santorum is at about a quarter), and there are some states ahead that should be good for Romney even if he falters. Under those circumstances, I don't think Santorum getting 41% of the delegates would be enough for him to be handed the nomination in Tampa. He needs to dominate the race going ahead, not simply run competitive with Romney, and he needs to convince the party that Romney is not a viable general election candidate.