Most governments wont want to let a a bunch of stoners write their own laws on an island which that government sees as it's own. What you really need is an independent sovereign state. Unfortunately I don't really think that you can buy them on the open market due to technicalities. However, all is not lost. You can "take over custodianship" of the Principality of Sealand for a cool $900 million, and I'm certain that you can write your own laws. It's not totally officially a recognised state, but they maintain they are and it's about as close as you're going to get.
http://www.sealandgov.org/
http://en.wikipedia.org/wiki/Principality_of_Sealand
Sealand is a bit nuts- I actually used to work in the seas surrounding it during my late teens. Basically it's an old anti aircraft fort/base from World War 2, built on legs in the sea 7 miles off the English shore. After the war the initially fell into disuse, before enterprising pirate radio operators realised they were outside the limit of territorial waters (at that time it was 3 mile limit) and it was a perfect place to broadcast from, immune from the authorities. Then in the late 1960's a former british army major captured the fort for himself and kicked off the radio dj's. He wrote his own constitution for the place, produced his own currency, postal stamps and passports, and declared it his own country "Sealand". Higher level recognition came after an attempted 'coup' by the prime minister of Sealand (assisted by German and Dutch mercenaries), which in the end led to the prime minister being held in the fort on a charge of "treason to Sealand". The Prime Minister also held a German passport, and so the German government became a little concerned. The UK courts were powerless to enforce his release, and so a German diplomat had to make a visit to the island in order to secure the PMs release. But the PM still claims rightful authority and maintains a "goverment in exile" called the Sealandic Rebel Government from his home in Germany.
It still goes strong today- Around 150'000 Sealand passports have been issued and you can, for a fee, become part of the Sealand aristocracy and be a Lord or Lady. The 2007 census shows 27 inhabitants with literacy of over 95%, GDP of $22'000 per capita and 0% below the poverty line. I've no idea what their attitude towards MJ is, but I know that at one time Wikileaks were thinking of basing their servers there, and Piratebay also attempted to buy it. This year an online casino is apparently going to be opened from the 'principality'. Maybe it would be a great location for a grow op too!!!
It's mad. It's a shame that most of these loopholes have either already been found and exploited or closed up; I'd like the opportunity to rule my own island too.
