I'm planning to make an own aracade custom stick. Therefore I played arouns with the buttons (Seimitsu PS-14-GN-CP, weiß) and the result was little button led mod. The led will be illuminated on press.
Taken the micro switch and drilled a hole.
Kynar 30 wires fits in .
LowCurrent 3mm led in red.
Here with button case.
Sorry for bad quality.