Would the Republican establishment "backstab" Trump if he wins the nomination? If so, how?

I know the GOP establishment isn't some monolithic thing, but they're pretty close to a monolithic thing when it comes to disliking Trump. More fundamentally, no power structure readily parts with their power and prestige. Losing the nomination to Trump would be the political equivalent of getting KO'd with a super-sized dildo. Do they deserve it? Maybe, but that's not the conversation I'm interest in.

The craziest scenario I can imagine is if the establishment actually tried to cut a deal with the Democratic nominee in exchange for undermining/"un-supporting" Trump. That's probably not an option if Sanders is the nominee, but I can see Hillary being willing to make some concessions. Perhaps that is too far flung... I dunno. But I do think a degree of cooperation and outright sabotage are very real possibilities.