This Module is currently available.
Rework of Moog's classic 904A filter and CP3 mixer
This is the single width version of Oakley's Discrete Ladder Filter built by Lower West Side Studio
Not to be confused with the Minimoog Transistor Ladder Filter the Oakley Modular Discrete Ladder Filter provides rich, resonant sounds using circuitry based on Moog’s 904A filter and CP3 mixer.
If you desire that thick Moog low pass sound then the Discrete Ladder Filter by Oakley Modular Systems might fit your needs perfectly. This module is a reworking of the classic 1960’s low pass filter module using the circuits from the 904A filter and CP3 mixer and combining them into one excellent sounding module. The module also features a drive control which allows you to heavily overdrive the filter circuit without producing a big change in output volume.
The Discrete Ladder Filter comes in a 1U width with 1″ (25.4mm) knobs controlling 4 potentiometers. The remaining potentiometers control Frequency, Resonance, Drive and Depth for CV Input #2
Two separate audio inputs are available plus two control voltage inputs. A 1V/Oct input available for keyboard tracking.
The module operates at +/- 15V and comes with a Synthesizers.com style power connector.
https://richsstudioproject.wpcomstaging.com/product/discrete-ladder-filter-1u/
These merchants probably sell this module. Huh?