Nah, Trump running third party would hand over to Jeb his 15 min of me too fame. Even if Jeb got nominated, let Jeb flounder on Jeb, without having to blame Trump running third party as an excuse.
I agree with that actually. Mind you, I don't want Trump running third party but it's kind of like saying, I don't want a tornado to tear through my town. A Tornado is going to do what it is going to do regardless of what anyone wants it to do. And when it comes for your town, you only have so many options.
If Jeb is the nominee, it will make no difference whether Trump runs as an independent. It will be a repeat of Romney, McCain, Dole, or whomever the GOPe anoints to be defeated by the Dems. History will repeat itself, and no lessons will be learned.