You are going for an entire community then, in which case I would recommend you actually form a Village and have self-government. (City is too complex). Now Disney in Florida even made its own county, but I doubt that will happen again. Still, a Village can be very powerful if you can do all the development up front. Set up police, fire, even schools, and public buildings and systems with survival in mind. What an opportunity. However, as it grows, the survival mindset of those started it is likely to be diluted, and that will show up in elections over time. As a primary residence community, I think it will be hard to get such a concentration of survivalist in a small area, thus I have gone toward the recreational retreat community or condo idea, thus pulling them from all over to an area with good survival capabilities.
I agree how great it would be to form an entire community with all that, but very few from my experience can afford that, thus I have trimmed down my dreaming. In fact, in polling I found $10,000 down and $500 a month was about the maximum you could expect from even the upper 10% of survivalists toward a retreat (besides their home). This is one reason I started with the condo idea, but for people with even lower budgets, I think the best solution is a trailer park/RV park lot. Now this would involve having well, gray water, and black water hook-ups with a common septic system and well, common electric off-grid power, a common building/bunker which will preferably be an earth shelter or concrete dome (i.e. www.monolithic.com [1]) with community bathrooms, showers, and kitchen and emergency housing, so it will stand up to a tornado even if all the trailers are lost. You make a good point about single source point failures, thus have dual systems set up would be a good idea, and over sizing them, so if one goes down, the other can pick up the slack. Hardened storage would also be good idea. Selling a very small lot for $5,000 would provide a lot of money for such improvements, maintained by a reasonable monthly or annual fee. Also, such lot could be leased out when that person is not there, just have a clause that they can be asked to leave within 24 hours and refunded the money, or some sort of escape clause if the owner is bugging out the site. Used hunting trailers around here are around $2,000. It seems to me the least expensive option. Once again, good to be near some farm land and an agreeable farmer for food production. – Rourke