There are two libertarian groups that are already trying something less drastic. They pledge to move to a specific area and slowly "take over" and change the place via running for office and/or voting for libertarian candidates and bills. Checkout:
http://www.freestateproject.org/
and
http://www.freestatewyoming.org/
Outside the US, I hear Costa Rica and parts of Mexico around the Sea of Cortez have ex-pat enclaves with libertarian atmospheres. The one in Mexico raises some concerns due to the drug wars in the country; Costa Rico less so
(Yes, I realize Objectivism and Libertarianism are not the same - but I think adherents of each could co-exist nicely...)