There should (hopefully) be an ~official-nix version of the detsys installer in the ~near future. (That said, one slice of the reasons this has taken a while is that the upstream Nix variant is obliged to stick to official features for now.)

It's basically at the point where it just needs a redirect from the nixos.org domain, and for the project/community to work through how to manage its development/relationship to the Nix repo.