Would you prefer fraud be a criminal offense? That would still satisfy libertarian principles. In my example, your neighbor could then be arrested for breach of contract, then you could still pursue your civil case.
And as for these deeded communities, well how big should they be?
The market would decide that. Higher demand will bring more and larger communities.
How much trouble would it be to get an entire city under one deeded community?
Depends on the city. In most cases it wouldn't be easy (not impossible) to get a whole city to agree to a contract, yet those are the problems free people face. We aren't utopians you know, and never said liberty would be easy or free.
It appears to me this has already been taken care of by our founders with states. States then decide what decisions can be left to counties and cities.
You and I both agree on the 9th and 10th Amendment and the ability to establish such places, and we agree that this right is no longer recognized. It is said that SCOTUS sees the 10th as a dead letter. It seems we have a common foe here.
Indeed. And I will gladly fight with you to get the Constitution to be once again respected.