A good comparison of what Google's probably looking for here is what Disney managed with Disney World: A special zone that exempts them from a lot of regulations, or allows them to set their own. Similarly, of course, Disney was hoping to build a "city of the future" there. The difference is, Disney got permission to do this in the middle of nowhere (literally swampland), and Google's hoping to get this authority inside a major metropolitan area.

I watched a video recently on it here: https://www.youtube.com/watch?v=aeWOc-cjfY0 ("Disney World's Private Government", 8 minutes, decently informative)