Stone Grey Distortion Modernized mod is a Custom Series, Limited Edition, Mad Professor pedal.
Limited Edition Pedals
Walrus Audio Deep Six Compressor V3 Limited Edition Effects Pedal | Guitar Center
Boss DS-1 40th Anniversary Limited Edition Distortion Pedal
Guitar Pedal X - GPX Blog - EarthQuaker Devices Unleashes More Pedalboard-Friendly V2 Version of their Limited Edition Sunn O))) Life Pedal Octave Fuzz/Distortion
Dust & Grooves – Adventures in Record Collecting. A book about vinyl records collectors » Vintage & Rarities: 333 Cool, Crazy and Hard to Find Guitar Pedals [Limited First Edition]
17 top pedal makers join forces for limited-edition black stompbox releases at Reverb | Guitar World
Amptweaker and Bassist Tim Lefebvre Collaborate on Limited-Edition TightFuzz - Premier Guitar
DISC Way Huge Limited Edition Geisha Drive Guitar Pedal at Gear4music