@tomerd - It would be nice to include a link to the package registry specification additions in the OP. They were part of the pitch and very informative.
As mentioned in the pitch thread, I am +1 on adding this. It's a very useful thing to add to the package manager and other tools.
I think the async status response and failure responses should be able to include a body, with a list of pending jobs that can be displayed in the UI while the user is waiting. Example.
It may take a bit of time to come up with a good data model for that response, but I think it would be a very, very valuable addition.