Other stuff
Brokered Democratic convention: 20
Michigan re-vote: 45
Both of these are too high. I've already explained countless times why a "brokered convention" as Intrade defines it isn't going to happen. (Hint: If everyone votes for one of two candidates on the first ballot, one of the two will get a majority, unless there's an exact tie.)
John Edwards has not released his pledged delegates. He's under no obligation to either. A brokered convention is entirely possible, even if there is no tie.
It's a very small number of delegates, and even if Edwards holds the balance of power, he will presumably cut a deal *before* the convention, as there's nothing really to be gained by waiting until August. Anyway, even if a brokered convention is a remote possibility, it's way overvalued on Intrade.