Stumbled upon this one on the Guitar FX Layouts forum. I already built a Ram's Head and an OpAmp Muff from GGG and thought this one would be a nice addition. Used 2N7000 MOSFET's.
Really like the tonestack of this fuzz, you can dial in a great deal of different tones. The Guitar FX Layouts forum thread reports this effect could be prone to oscillation but I haven't run into that issue so far.