I hardwired the external controller port for player 1 to the Nintendo 64. Then wired the internal controller through a micro limit switch in the normally closed position. And finally the switch was glued in such a way that it is opened when a controller is physically inserted.
Lol, speaking dimensionally I forgot to post those. It's about 13.5 wide x 7.375 tall x 1.375 thick. My goal was to come in under 1 inch thick but that didn't work out because of the controls. And it didn't feel right putting DS Lite controls on such a massive portable. So in the extra space I doubled the battery capacity.
Also here's some proof of the RAM swap and built in Memory Pak.