It is possible to write a script that mirrors the registry, packages, and artifacts and set up a dev image that respects it. The script basically just needs to use Pkg and Base. However, artifacts end up taking too much space and then you have to decide how to host only a subset of package versions intelligently and propagate that change through at least the registry and artifact mirrors.
I went far down this path before infosec agreed to give github / highly respected cdn access.
I went far down this path before infosec agreed to give github / highly respected cdn access.