I opened a preliminary PR (open-services/open-registry#10) for Federation but probably best to go via a issue first, to better enable discussions around it. Here is what I've been thinking so far.
This proposed feature of Open-Registry opens up the ability to federate servers for serving the tarballs for the registry.
Running a global network of the scale of the npm registry will be impossible to do with just being funded by the community as the costs will be too high.