Rather than talking about splitting off from the Republican Party to form a third party under the argument that the Republican Party is really just the Democratic Party in disguise, what dissatisfied conservatives should do is work to build up the existing party back to conservatism. If you think the Republican Party is invaded by liberals, then work to push them out! But, we must absolutely be careful not to split our cause.
I am of the mind that, rather than start dividing on the Right, we ought rather aggrivate splits in the Left. The Left in general, and the Democratic Party in particular, is made up of groups with a wide variety of agendas loosely tied together for the sake of spreading their radicalism. We should think of ways to split THEM into third parties, not ourselves, and then push the leftists in our own party to join them. That is far more viable a solution than splitting ourselves up and expecting to make any real progress, IMHO.
And how long do you suggest we wait for this to happen? 10 years? 20 years?
The Republican party will not return to conservatism in my lifetime.
They will just continue to offer us all a slower trip to the New World Order.