Right now, only linux (perhaps only NixOS to be specific?) has support for chroot builds; it would be nice to have support for Darwin. On linux, this accomplished with bind mounts and chroot; on Darwin we could use bindfs and chroot (assuming the user installed bindfs).

I would be willing to take this project on (you can see my level of commitment in my previous XQuartz work), especially if one or more core members would be willing to make a best effort to be available for questions/advice.