Ahh no. Even buying an uninhabited island from a country wouldn't work since no one would sell it to you and secondly, almost every island in this world is already under the sovereignty of a country. Besides, some countries are trying to put one step forward towards bitcoin legalization, one of which is Australia. Also by legalizing bitcoin means submitting yourself over to the government's control and you're allowed to use bitcoin under their mandates. Would you even like that?