Libertarians tend to win state assembly seats in more conservative states. I don't believe they've ever won seats in the states you've mentioned.
Although the presidential candidate has never done well in elections other candidates have made excellent progress on the Congressional level. Carla Howell holds the record for the most votes in a Congressional race. She recieved over 300,000 votes in Mass in her bid for Senate against Ted Kennedy (roughly 12% of the vote). In some state assembly races Libertarian candidates recieved over 40% of the vote.
Weaning people off the two incumbent parties is difficult. Both Republicans and Democrats promise a smorgasbord of government programs and handouts. Libertarians do not. Libertarians have managed to place a measure on the ballot in Mass which would repeal the state income tax. There is massive opposition to the idea even from common folk. It's as though people like the feel of leg irons and they don't want them removed.
What exactly are these states where libertarians win legislative seats? I was using those as examples because they're very sparsely populated. They're also much more conservative thatn the country at large. A state legislative district in some of the western states probably has about 10,000 people. These states are not evidence of libertarian viability. The Presidential races are a measure of Libertarians' real viability nationwide.
If I lived in Massachusetts I'd probably vote for some third party candidates for legislature and governor. For one thing, the GOP is so hopelessly behind in seats in the legislature that it can't be plausibly claimed that voting for a third party is tantamount to giving Democrats control. Secondly, the Republicans in Massachusetts would be considered very liberal in many other parts of the country, like their current Republican Governor. If Mitt Romney runs, I'd vote for him if I lived there.