Hi Ben,
my idea is a gamepad switch. sometimes i would love to use my xbox360 gamepad with other consoles. thought about a box with different gamepad(PSone, Nintendo, Xbox,USB) inputs and 1 x USB output (PS3/PS4/XBox360). 2 Switches controlling the in/output-mode. you could use old gamepads for the console-gamepad verification. calibration could be a problem. a raspberry as included calibration/button-mapping tool would be great but i am not sure if this cause latency issues. a button for y-axis inversion, rapid-fire and other hacks are possible too.
Love your show!
Thomas