A good long read.
http://reason.com/archives/2013/05/13/the-blank-slate-state
Basically the Honduran president's chief of staff is a libertarian with dreams of free cities. He was able to talk the president into giving it a trial run. After some comprimises getting the law passed through their congress it was set to go. But then it was fought at the Supreme Court level and overturned. It was overturned mainly for political reasons dealing with backlash against some corrupt politician.
Now they are back at it drafting a new law that would fit within their Constitution and be able to face the scrutiny of the Supreme Court.
More than likely, as things tend to go, the better the idea the more special interests will want to get involved to get their cut thus diluting it to the point where when it finally makes it through it is a bastardization of the original idea and will fail for those very reasons.