a brokered convention and the true believers:

[customerserviceguy]

7. For the reasons the OP states

I don't think it will be someone picked on the second, fifth, or even twentieth ballot. They'll all be true believers in there, and they'll all have smartphones keeping them in contact with what the outside world is saying about the mess. They'll have their feet held to the fire by the candidates who put them there, and by folks back home.

After about the fiftieth ballot, the Repuke nomination will be seen as a thing of very little value this year, and nobody who wants a shot at 2016 will want to be anywhere near it. Some sacrificial lamb will be found to nominally populate the top of the ticket, and another stooge will be found as running mate, and Republicons will spend from that day until Election Day, fighting, carping, and smearing each other over the chance that got away to defeat Barack Obama.

It's my dream scenario, but it could happen.