Proco Rat that I modded the f*ck out of:

It has switches for Silicon, LED and asymmetric clipping (1 Led / 1 Si), Ruetz Mod and OD/Distortion (in OD mode the diodes are connected over the op-amp, like a Tubescreamer)
Also simplified the input stage, no buffer (Similar to schematic on Tonepad.com), lowered the input cap to 1n as I found it too muddy and bassy (maybe that's just part of the Rat sound, but I like it better this way)
For anyone interested,
check this post on my webpage, has a link to schematic and vero layout (altough not very great you can at least see how the mods work)
Edit: I forgot, I built the pedal to use as a reference for
this projectBasically, I'm doing a digital simulation of the Rat and it's going pretty well.