Found the schematic for this over in the Aron Nelson Gallery. It's designed by Scott Frein. Uses a simple JFET buffer to help push the transistor-based drive section. Here's his description:
A pretty simple overdireve. The buffer on the front really brings it to life. Good AC/DC,ZZ Top crunch from this. Hit it with a booster and go from JCM 800 to Fuzz.