I've also recently retrofitted my arcade with a RPi3 and Recalbox. I'm really pleased with how this turned out.
I build this arcade over three weekends (about ~6 hours per sat**day), followed by a week of frequent application of polyurethane. The controls are Seimitsu PS-14-GN buttons, and Seimitsu LS-32 sticks. Although no longer necessary, I used an Ultimarc iPac keyboard encoder for the input. I am especially pleased by the lack of screws on the playing surface, the Mario themed inserts on the command buttons, and the general craftsman style appearance.
A lot of details were taken from the site: http://www.slagcoin.com/joystick.html.
Final appearance:
Testing the RPi3 for the first time. I was really pleased with the performance even with "demanding" PS1 games.
Details of the controls
Details of the wiring
