I'm have 26 NOS Wico micro switch 8 ways that might be perfect for a RGB LED conversion. I've done the LED conversion to a Happs Super with U360 parts for control. I kinda like the rubber grommet of the Wico, and think if the shaft was keyed to the ID of the grommet (to prevent rotation) no line jack would be necessary. 4 pole line jacks are somewhat rare and expensive. Might make an interesting project.
Cornchip.