Large-L Libertarians (members of the LP) do NOT represent mainstream libertarian thought. However, folks who consider themselves small-l libertarians or, more recently, South Park conservatives are, in my opinion, far more conservative than your typical mainstream Republican.
I can be described with the South Park image, since I believe in liberty and eschew conformity. Conformity is what I find on the hard-right, which makes it terribly unappealing to me. In keeping with one of the creators of the South Park cartoon, I agree (though I won't use that language) that "I hate conservatives, but I really f------ hate liberals."
I didn't escape one form of mental bondage only to reshackle myself to another. Therefore, the arguments about who is more conservative than who bore me. Just one big yawn.
Fiscally, perhaps, but not socially. I think when it comes down to it, the social issues are what best define conservatism at the foundational level.
"folks who consider themselves small-l libertarians or, more recently, South Park conservatives are, in my opinion, far more conservative than your typical mainstream Republican."
The label "Conservative" is too hard to define. It doesn't really mean anything in the literal sense. If by conservative you mean the roots of the conservative movement from the days of Goldwater, then yes... libertarians are alot more conservative.
This is not true. Every libertarian think tank that I have ever heard of is favorably represented with in the LP. The LP gets almost all its guidance either directly or indirectly from the many small "l" libertarian (as you call them) organizations and publications. The only small "l" libertarians who reject LP positions ("thought") to any significant degree are extreme anarcho "voluntarists" who reject all group organized activities (including all political parties) on principle as being collectivistic, choosing the Aquarian Conspiracy model of independent action instead. For similar reasons, Randians also significantly reject LP "thought."
The fact that most libertarians reject the LP has nothing to do with LP thought. The rejection of the LP by libertarians at this time is mostly based upon priorities and political strategies. Thus most mainstream libertarians can be found as either Democrats or Republicans.