Just for the sake of completeness, after much googling I came to learn that what I was trying to describe already has a name, and it's Arcology: http://en.wikipedia.org/wiki/Arcology

So I mean that we should use arcologies (am I using this word correctly?) to experiment with finding the best political systems for each person, by allowing each person to choose where to live, and fine tuning the laws of the least popular arcologies to try and attract more people.