A while back I ordered from Japan some Sanwa joysticks and buttons plus a `Zero-Delay' usb encoder for a Raspberry Pi MAME project my son was working on. There was no soldering required. The supplied cables had the appropriate connectors fitted to push onto the joystick/button contacts and plug into the encoder pcb sockets. The pcb then connected to the Pi via a USB lead. Simple.
![Smile :)](./images/smilies/icon_e_smile.gif)
So my idea is a small pcb that fulfills the same role as above, ie, allows anyone to connect a stock Japanese arcade joystick and button using the stock cables, but has a lead running off that plugs into a Dragon joystick port and performs the necessary digital-to-analogue conversion. And users would be free to source their own enclosure, joystick and button (there are lots of colours and finishes to choose from).
I did start looking into a simple circuit using a 4066 chip but to be honest this is out of my comfort zone.
![Crying or Very Sad :cry:](./images/smilies/icon_cry.gif)