I wouldn't rate Bill Bradley as unlikely as BRTD does. He'd be an interesting sleeper bet were he available for less than 0.5 on Intrade, IMO.
In terms of likelihood, I still put Sebelius at the top, but otherwise I don't know.
I really wonder why Bayh got more mention than Sebelius. Neither is from a swing state. Sebelius is a brilliant politician and one of the most effective. Bayh is an extremely boring and uninteresting guy who has nothing going for him but his last name.
I suppose it's the idea that hordes of Ohioans would just melt at the thought of voting for a ticket that includes a guy from a neighboring state on it.
The fact that Bayh was a potential candidate for President is probably a reason his name has been mentioned more.