No info about availability.
Mankato VCF
Resynthesis Magic Smoke Mankato VCF Synthesizers.com Panel only (for DIY) 6, 12, 18, and 24 dB/octave outputs, inverted 6, 12, 18, and 24 dB/octave outputs, 45 degrees of phase difference between each output, 8-phase sine wave oscillator or LFO
http://www.bigbluewave.co.uk/resynthesis/resynthesis_front_panels.htm
These merchants probably sell this module. Huh?