I can't claim complete credit for this TBH. Todd is the one building the amps, and an RGB SCART cable/ connection using the expansion port has been done before. I was just mulling it one day whilst modding a PC Engine for someone else, and noticed that all the feeds went out to the expansion port. It was just a case of putting 2 and 2 together after that really.
Like I say, it has been done before, but I have to admit, not in quite as neat a way as it has done with this cable.
I will one day get around to building a full rear connection that powers the system too, although it would need it's own fuse and switch etc, but for now it's on my To Do pile.