Available as an assembled Module and as a DIY project.
This Module is currently available.
Independent panning of 2 signals
This is based on an extremely rare 100-series module that used JFETs as VCA control elements. It behaves imperfectly but has a great, throbbing, musical sound. The switches on the front allow configuration so that the two inputs will "ping-pong" or track each other; or when using it as a 2-input voltage-controlled mixer, ensuring that both responses behave similarly to envelope control.
These merchants probably sell this module. Huh?