Two North East guys on one ticket? Not likely.
You are correct. There is no way Romney would put Christie or Santorum in the 2 hole. He has to throw the rest of the country a bone so they will hold their nose and vote for him.
I think it is a mortal lock that Perry will be his running mate. Perry is from the south, a socon, and won't outshine him.
Look, why did Perry, after coming in 5th in Iowa, say he was going home to think about continuing, and then get back in? Nobody makes a statement like that, and then has success. Methinks Romney talked to him about getting back in, to try to dilute Newt/Santorum.