So, union mountss ? This looks a lot like what plan9 used to propose: http://www.cs.bell-labs.com/magic/man2html?man=mount&sect=1 http://www.cs.bell-labs.com/m

So, union mountss ? This looks a lot like what plan9 used to propose: http://www.cs.bell-labs.com/magic/man2html?man=mount&sect=1 http://www.cs.bell-labs.com/magic/man2html?man=mount&sect=1 with the added feature that each sub-fs is independently distributable, which is very good. I fear tying it to btrfs (or any specific fs) might be a bit much though. I don't know if that could be possible by mounting upstream tarballs as read-only fs in userspace... maybe a crazy idea.