I found the (hand drawn) schematic for this in the depths of FreeStompBoxes, so can you hehehe. Never got to build it, but doesn't look bad at all. The schem reminds me of the ROG Supreaux. Here it goes:
Even though I tried it for only 5 minutes using a test box, it sounds really good, IMO. Reminds me of one of my favorite OD circuits, indeed - the ROG Supreaux. However, this one has a more efficient tone control and an interesting and toneful feature in the "sag" control.
Be aware that increasing the tone control also increases gain (its more of an upper midrange thing) and increasing the sag control adds gain and fatness at the same time.