@ts-x Great idea on dropping in on him. I might just do that. I have a wired number pad that I tried to use plugged into the USB port on my Mayflash (which would also avoid two long wires), but that didn't work. It's not a real USB port apparently. However, it would also be seen as another input device.
This issue is NUTS and across the whole retro industry. Someone needs to do something. Every joystick should come with the ability to ID itself as unique. If say, 8bitdo suddenly started offering controllers that all could send out unique IDs it would be a SHORT wait for someone in Retroarch and others to jump in and support that. That manufacturer would sell a ton of product and force everyone else to adopt that option as it would be SO brain-dead obvious. How has this NOT happened yet???