CV Controlled Matrix Mixer
This one has 8 inputs and 4 outputs, under the hood are 32 VCAs and 4 mixers. The proto-type worked well, just needed 2 links added and a few resistor values tweaked to get unity gain for a 5V CV. Using a solder-paste stencil and reflow oven, it takes about an hour to get all the surface mount components attached....by hand I dunno, not keen to find out either :)
http://nonlinearcircuits.blogspot.com.au/2015/03/cv-controlled-matrix-mixer.html
No info about availability.