The ones that other people claim to do are just based off of the schematic that was on SLO Clones and there are a few errors in it. That's why the "Snorkler" mods don't sound as good as the original.
Didn't he do quite a few for Jerry Cantrell trying to replicate the Snorkler and according to urban legend they did not measure up to the original from what I have read. You would think he would be able to do one quite easily...