I'd love to hear more about the potential of Nix for language agnostic isolated development environments: https://nixos.org/wiki/Howto_develop_software_on_nixos

Could it be a unified alternative to Python virtualenv, rvm, rbenv, cabal sandbox, etc? This would be specially important for projects needing heterogeneous builds.

It'd also be interesting to see a typical Nix development workflow taking advantages of Nix goodies like continuous integration with Hydra or staging and production deployment with NixOps.