Simple 2HP multiple for eurorack. Has 6 holes drilled for 1/8 inch jacks. Can be wired up for 2x3, 1x6, or whatever you want.

Unfortunately a 2HP panel is pretty flexible. I made this about 2.5mm thick which is about as thick as I could go with still allowing the 1/8" jacks I had to fit but it still flexes a bit. It may be better if its printed with something other than PLA possibly.

10mm wide x 128.5mm tall ~ 2HP