I don't know about a replacement for Klinton at this stage but strategically speaking Trump is far better off facing her in the general.
Getting outside of the closed society at 24hcf I see a lot of folks who don't like Trump because they're scared of him as a loose cannon but they think Hillary is far worse, they know she's a flat out criminal. Mostly they are Bernie fans.
If it's Trump vs. Klinton I see Trump with a clear, quite possibly landslide win because the Bernie voters/Trump haters stay home while the Bernie voters who are ambivalent about either candidate vote for Trump as the lesser of two evils.
But if you take Hillary out of the game and put Bernie in I'm afraid Trump has some serious competition. I don't really know the ramifications of some other Democratic candidate pair but the Trump haters would most likely have someone they could at least hold their noses and vote for, just like straight R ticket voters had to do in the last two elections.
I say we start a huge email and call-in campaign to the DNC demanding that they support Hillary and make sure she gets the nomination. It would be to Trump's best advantage...
