Found this on the gearpage messageboard...
http://www.thegearpage.net/board/sho...php?p=13713327
Looks like analogman did some work on one of Thurston's main big muffs (a tall font green Sovtek) made it true bypass but had to include a relay to maintain the original fatty bypass switch.
I saw a few recent vids on youtube of Thurston using this and some unknown pedal (between the Rat and Big Muff) from a Chicago festival in November. It looks like custom analogman pedal, a King of Tone or a Bi-chorus form the number of knobs/switches, the vids are not good enough quality for me to exactly determine which it is... not sure if he would actually use a chorus??? it appears the pedal he's holding in the pic on the gearpage with his brother Gene and Analog Mike is indeed that bi-chorus though...