There are a couple of places where "power beyond" is available. The backhoe uses one and that would be the answer.... but that's already in use with the backhoe connected - as it usually is.
I believe that when mike ordered the rear remote option that it uses a a factory plumbed connection to the rear distribution block to run the rear remotes. It sounds to me like mike is looking for an additional full flow power out port from his rear remotes valves. I don't have the rear remotes on mine....so I don't know all the details on that system. So I listed some options. None of those I mentioned are strictly Kubota OEM - but they will all work.
Kubota might have yet another way of doing it with factory parts. But if so I don't know it and don't see it in the manual.
luck, rScotty