Available as an assembled Module and as a DIY project.
No info about availability.
CGS UNI33 Matrix Mixer
Single panel for the CGS Matrix Mixer. PCB by Ken Stone (CGS), panel by Loudest Warning:
http://www.cgs.synth.net/modules/uni33_matrix_mixer.html
These merchants probably sell this module. Huh?
Included in 70 Racks, 24 are public: