This Module is currently available.
3 channels mixer + inverted out
This module allows you to mix up to three input signals, either audio or control voltages. Each of the inputs has a dedicated knob to control the overall mix and you also get an inverted output.
http://www.addacsystem.com/product/addac800-series/addac801-simple-mixer
4 Users are observing this
These merchants probably sell this module. Huh?