So I did a couple of custom builds of these recently, based on The Gristle PCB from FuzzDog.
I ordered a few more boards + faceplates and am building a few extra to sell.
They are completely hand built and hand wired.
The Gristle pedal is based on The Gristleizer, a modulation effect used by the band Throbbing Gristle. It was a circuit designed by Roy Gwinn first published in an old electronics magazine, and modified by Chris Carter (of T.G.)
It's a Fuzz / Tremolo / Filter all in one and a lot of sounds can be made using it.
[UPDATE] I've made a 2nd batch of 10x pedals. Once these have sold I'll be making my own PCB so I don't have to do so much bloody wiring.
[UPDATE 2.0] I'm out of parts for the CV mods too. You will have to wait for the Gehirn version for the CV mods to become available again.