Don't hold your breath. The establishment GOP is hopping behind Trump for one reason and one reason alone...bring down the most conservative candidate, Ted Cruz.
They will then jap Trump during a brokered convention. Would not be at all surprised to see an establishment GOP RINO win the nomination. Bush ain't goin away. Neither is Rubio. Trump will go in to the convention short the 1236 delegates needed to secure the nomination.
If Trump does win the nomination, I will support him against the democrats. It would not at all surprise me if Trump turns on his liberal NY tendencies as POTUS. We all thought Bush was conservative, turns out, he was much more liberal than most had anticipated. Will see.
They will then try and unite the rest of the Republican Party behind Marco or Jeb (or maybe even Kasich or Christie) - whoever can "surprise" and do well in either Iowa or New Hampshire.
And if their efforts to rally 1 candidate to defeat Trump then they will do whatever underhanded means they have to to try and stop him (possible brokered convention, etc...)
Life will be so much better if Cruz can win big in Iowa, use the momentum to surge to a shocking win in New Hampshire, and then win in South Carolina and propel himself to the GOP-nomination.