I found this Custom Cable Creator. Pretty awesome! You can pick from a very wide variety of plugs and sockets and custom make a cable, then order it! Not sure what prices are like, I suspect high, especially for low volume.
I’m getting a RD6006W USB/WiFi DC voltage bench power supply with the S12D case. I’m gonna power it off an old ATX power supply. So I needed a molex to banana plugs cable, and I made one:
I threw a DC barrel power jack on the 5 volt line. Finished with heat shrink tubing, my new favourite thing.