VERY VERY little....it will end up eventually being one of the three, my money tho is on Bush or Rubio over walker.
I agree. The chances of it not being any of those three is 5% or less. (And I don't think Walker is a viable national candidate, solely because of how he handles interviews. He's close to Palin-level already.) Perry, Jindal, Pataki, and Christie could theoretically be serious candidates, but are extremely unlikely to gain any traction, mainly due to their own flaws.
Rand is a "kook" and rejected by a good swathe of the establishment. Kasich might have an outside shot... there's the real dark horse. (Idk if his Lehman Bros. experience kills his shot at the nomination or not - it could certainly be used to finish him in the general.)
Carson, Cruz, Fiorina, Graham, Huckabee, Santorum, and Trump are not serious candidates, any more than Vermin Supreme, even if the media likes to pretend that they are. (If any of them do get them nomination, it will only be a sign of the Republican Party's decay.)