I don't think he'd agree to be vetted for Trump's short list. For that matter, should Trump be nominated, the list of people who refuse to be vetted for Trump's short list will be rather long. Most of the "establishment" guys just are not going to want to spends several months talking about how much they love Trump, nor defending whatever outrageous comments he makes.
Plus, most of them don't think Trump can win. They'll figure that they have a better shot of being president if they avoid Trump, wait for him to lose, and then run again in 2020.
I imagine the vetting process for vice president will heavily take into account how sycophantic the potential VP nominee is, just like the show the apprentice. There's a potential SNL skit somewhere in there...
