With the Republicans turning into Democrate-lite, with no true fiscal conservatives, and no true social conservatives, all that's left in the Republicans are the so called "neo-cons" interventionists and RINOs, I think it will go the way of the Whig party and another new party can rise up to take it's place.
If the fiscal conservatives, social conservatives and non-interventionist and libertarians can form an alliance, it can be a great force to be reckoned with and definitely challenge the progressive-social liberal-statists dominance.
Some tea partiers, so-cons, anti-war democrats, and Ron Paul type would not be even remotely big enough to make a winning coalition. I say this as someone who would love for that to happen... it ain't.
Plus you'd have the issue of this group being so fractious. How do you get Dennis Kucinich, Rick Santorum and Ron Paul to agree on a cohesive platform?