Nearness Attenuated
Nearness is a simple but effective panning mixer. Seven inputs, two outputs. The closer an input is to an output, the greater its influence on it. This is a remixed version with attenuators on the output so you can adjust the volume of each signal.
Resources:
I got the PCB and panel made from JLCPCB from the gerbers in the Github repository. This was a really easy and straightforward build.