It sounds like you're describing a traditional mobile home. That part is already "solved". The other stuff is site specific - well, septic, solar, etc. Perhaps

It sounds like you're describing a traditional mobile home. That part is already "solved". The other stuff is site specific - well, septic, solar, etc. Perhaps there is a market for setting up sites, but the site development items are so unique to each site in an off-grid dispersed scenario. The actual house part is readily available though, full specs and all.