I don’t think any serious democrat challengers will emerge against Obama in 2012. Even if they won the nomination by taking the vast majority of the white democratic vote, they’d lose the black vote in the general election and surely lose to the GOP candidate. So a democratic challenge to Obama is a no-win situation and you won’t see Hillary getting into that kind of situation.
..the Clintons will get even—even if it burns the whole place down IMHO...
There will be if Obama's Big Money donors start to get antsy. That money will be seeking a candidate. This is the Democrat Party we are talking about. The party where the sitting incumbent gets little respect and draws multiple primary opponents.