You can find Bajaman's original thread and schematic on the FSB forum here.
There are two versions:
First one with just one toggle switch to select between Cruch, OD1 and OD2.
The second one uses separate footswitches, Gains and Levels.
You need to add an extra pole for LEDs.
Can use any small signal N channel JFet for the buffers (mind the pinout).
