The Rust Bunny is my take on the Sam Ash Fuzzstainer, based on the tracing done by Jerms as posted on the Tone Machines blog (tonemachines.blogspot.com/2012/02/sam-ash-fuzz-stainer-197.html). A very, very rare noisemaker, but a very cool one that deserves more attention.
It plays nice with single coils or humbuckers, with a very effective tone stack for playing nice with different amps (it works well through either channel of my amp in different settings, which is rare). Especially nice is that it can be placed after another active pedal with no change in sound or behavior.
I made very minor changes to the original schematic: I added polarity protection and power filtering, altered the output section to retain more output (the original had to be dimed to reach unity), and limited the range of the bias pot to avoid cutting out on the lowest setting and to get more fine control over the usable settings. I used 2N5088s for the transistors -- it's not too picky, but it's worth experimenting.
A perfboard layout and etch mask are shared in my perfboard library on my website.