As I've written here countless times, I believe that the GOP presidential failure in 2008, which revealed a big divide in that party between small-c conservative "Buckleyite" moderates and the hard-core, far-right ideologues dominated by the Christianists, would result in a schism that would eventual create a third party. Sullivan compiles a couple of thoughts on the subject here, indicating that Americans are largely ready for a third party. But they have it wrong. What pollsters see as "independents" is really a mish-mash of people who only call themselves independents because they don't want party affiliation for whatever reason. There's nothing there to coalesce into a party, because there are far left elements and far right elements. If anything comes from the large body of so-called independents, it will be multiple parties, at least two. Once there is a third party, there will be more to follow.
You'll never get Libertarians to that level. Their reputation as isolationist nutjobs is nearly cemented, thanks to the press coverage of Ron Paul. Not to say that Paul has nothing of substance to say. But there's a huge conflict within his message that doesn't offer leadership; merely, a fountain of ideas to be refined so that all Americans can get behind them.
My bet is that Christianists are first out of the gate with a third party, incorporating far-right social issues with the prosperity gospel and Dominionism to make a claim for national leadership. All they need right now is a charismatic leader who sounds more reasonable than insane.