99% of us can't lay out the mula for an island. But, if you have a little ingenuity and madness, you can build one. British (of course he's British) artist Richart "Rishi" Sowa went to Mexico and built his own floating paradise. (mind you, it's all in the eye of the beholder) Rishi filled nets with empty discarded plastic bottles to support a structure of plywood and bamboo, on which he poured sand and planted numerous plants, including mangroves.
[youtube http://www.youtube.com/watch?v=w1MJEMeX9tQ&version=3&hl=en_US]
Thank God for eccentrics.