VCF based on Korg FK-1 pedal
This has a core based on the Korg FK-1 pedal, which is a similar VCF to the ones found in the 800dv, 770 and 700 synthesizers. These VCFs have low pass and high pass stages in series. The main difference is this version uses vactrols as the variable resistors.
http://nonlinearcircuits.blogspot.com/2015/12/fk1t-vcf.html
Module is available as a DIY project only.
No info about availability.