Crony capitalists aren't going to bolt the Republican party. They're going to stay right there insisting that they are the "grown ups" if only because they have the most money to finance and support what passes for them as "Republicans." Philosophically, that they are even in the party at all, let alone at the top of its 2012 presidential ticket, means I am apparently in the wrong party now.
UNLIKE ten or 15 years ago, now I am wiser and don't care what frikkin' party the candidate is in -- if he or she is a depraved amoral government pusher or worse, a morally bankrupt liar and overt cheater like Cochran, then I sure as hell will vote whatever way I can to weaken that candidate whether it's a Republican, a Democrat, OR BOTH. It's physics. Thinking you've just elected wankers like Cochran because it will help create a "good" Republican majority, is like thinking you can get away with making sweet orange juice from rotten lemons you've just purchased. It's material, it's physics. You get what you vote for, especially if what you vote for WINS.
From where I'm sitting, the scenario of "crony capitalists who bolt" the party looks like extreme wishful thinking. I think that unless a miracle happens in less than two years, the GOP will lumber forward nominating a leftist functional Democrat Republican for the 2016 presidential race. IF that happens, and your crony capitalists stay in the party, WE are the ones who will have to bolt to a third party.
The "holding their feet to the fire" thing can work in Congress with regard to Republicans, but it would always get a body blow the opposite direction under the administration of a functional Democrat Republican White House administration, especially if that president had a voter majority mandate.
It could even be that the best way to preserve the Republican party would be to vote "Independent" in 2016 so as to pull a Perot and make sure that whoever wins has a disgraceful plurality "mandate." It's the best we can do, and though I didn't vote for Perot, in retrospect I see that Clinton's plurality status both elections HELPED the Republican Revolution to succeed.