Interesting idea.
First, I believe that in an ancap world something like that would come to pass: most city blocks (excepting downtown areas) would come to be owned by either co-ops or by entrepreneurs who would rent out apartments to customers and require them to follow some code (hence one would be able to chose the moral restrictions in vigour in his community).
But that would be quite different form a state simply because: 1) you can flee if you want, and fleeing a neighborhood is much easier than fleeing continental USA and 2) no one is forcing you to rent a house/become a member of such firms/co-ops. If enough people feel like owning their houses, this demand will be satisfied.
Yet on practical levels I agree that a world of neighborhood-sized compulsory states would be almost identical to this ancap vision. The problem with states is size.