I'm happy to report: I've successfully modded an NES-04 controller into an arcade stick. Tested it with Contra, and it works perfectly.
Sanwa joystick, Suzo-Happ buttons, Cherry microswitches, if anyone's curious.
I'll update this thread from time to time with updates on the control panel/body design and build.
Edited by HeadcolorsTV, Sun Feb 24, 2019 12:45 AM.