Most are ideological soulmates of the Mittwit. Olympia Snowe, Susan Collins, Lamar Alexander, Bob Corker, John Cornyn, Nancyboy Kirk, etc., etc., etc.
My first choice would be Sarah Palin because she knows how to chum the water for easy fishing. My second choice would be Newt because his intellect would rap his enemies over the head with his rhetorical wit. However, Mitt will never pick anyone who could do him any good. He’ll pick another Dan Quayle who will be turned like a sausage on a stick until done. And Mitt, in the process, will be done.