Just a thought on what/how such a community might evolve:
What about the current model of gated/planned communities designed for seniors? I'm talking about planned communities like The Villages, built on private land where there is an extreme degree of autonomy from normal government. Andrew Blechman wrote about them in "Leisureville", which is an interesting read for sure.
If you take one of these golf cart communities and strip out the fancier amenities and add a little more modest housing, I think you might have something resembling an ideal community for mustachians - a recreation-rich community that's bikeable and built around sharing and economy. However, there are a few significant drawbacks to this type of community, the most obvious of which are the complete lack of schools (or any support for young people - this is a retirement community after all). Thinking back to my days in Chicago, something like 65% of our property taxes went to funding the bloated school system/local government, so this could be a nice way to create a leg-up situation for dedicated and/or aspiring FIRE-ees.
I'm not sure how practical/legal it would be to exclude kids, since the public model relies on everyone paying in to the current model.