Josh Green, writing for Bloomberg and still rooting around in the entrials (or does one mean detritus) of the titanic battle for last year's Repub presidential nominee, writes that a key moment when the anyone-but-Romney movement was almost evenly divided between backers of Newt Gingrich and Rick Santorum, the two men were in serious talks to merge and run as a ticket.
Green has attributed quotes from high-ranking lieutenants of both camps indicating that the talks were serious and came close to a deal, but you can probably guess what stood in the way. They couldn't agree on which of them would be president and which would be veep.