As people appear to be enthusiastic about this idea, I thought I would add my thoughts for consideration. I may not join for the present as I am not yet "retired".
1. It would be ideal to form a co-operative housing society and sell shares to members who want to own flats in the project.
2. There should be one bedroom hall kitchen and balcony apartments of appropriate size which will give the feeling of spaciousness. Just one bed room only because an old couple couple will find it ideal to have. All visiting relatives like sons, daughters, grand children can stay in the guest accommodation which should be separate larger flats with two or three bed rooms.
3. There should be a canteen block serving only veg. food and a dining hall. The society employed employees will maintain the catering and every other supporting services. Every month the daily menu will be decided by a small committee of residents.
4. A separate room for a visiting Doctor's consultation and an attached waiting hall should form part of the project.
5. A temple and a hall where individuals can sit and pray should be part of the project.
6. Park, walk ways, a tennis court and a indoor games rooms can be added.
7. A small hall where movies can be screened and viewed, pravachanam/kalakshepam can be held with a public address system is a must.
8. Wi-fi a must.
9. Security a must.
10.Grandiose ideas like secularism etc., should be avoided and like minded people with similar backgrounds should only be allowed to become members of the society.
11. Futuristic Solar power panels should be installed so that the whole group becomes self sufficient in their power needs and are able to supply their surplus clean power to the grid (with net metering facility).
Just some ideas. Good luck.