If he wants to be Santorum's VP, then stepping aside now would be stupid. The only reason Santorum would put Newt on the ticket would be because he needed Newt's delegates. So if Newt wants that to happen, then Newt's best strategy is to stay in and get as many delegates as he can. Eventually, the only states left will be winner-take-all states. At that point, Gingrich will no longer be able to get any more delegates and he will have more bargaining power with either Santorum or Romney, depending on his intentions. Based on everything he and Romney have said, I don't see a Gingrich-Romney team up as even a remote possibility.
For some reason I can see Newt siding with Romeny before Santorum. The irony is he is talking about how there is only 2 conservatives in the race now, but I think his true colors will side with the establishment Republican choice which is Romeny. Newt can’t change his stripes he is who he is, despite what we want him to be or the phony conservative he wants us to believe he is.