The part pictured in post #18 from KFM is the one but will probably be unobtanium for some time. It also seems like a very awkward solution to simply powering a top case. Large unnecessary flange around it, exposed back side, and a plug that will also have to be sourced. One could of course cut that off and splice on to it. A far more elegant solution would be to simply power it from the battery or a switched source like any other accessory. This would actually get power to the case right now without waiting for a part that's not currently available.