It does, You just replace libstubs metatable __call, and all LibStub("library") calls get proxied.
That code is commented out in my example.
What I meant is: you told us the example works and when I read the example, I'd say it might work. If the whole thing does not work, you should show us the whole thing and not the example that works. As Jerry pointed out, there are other methods to support and I could not tell if you added proper support from your example.
Jerry, isn't there some "metamethods" to support == ?