I have been calling around to different shops and they, too, have no idea what I'm asking about. I've tried such keywords as "smoked plexiglass, tinted plexiglass, transparent greyish plexiglass, etc".
BUT, there is McMaster near my city of Cleveland - what should I ask for when I call - the website lists all kinds of 'acrylic, polycarbonate, sheets, rods..." confusing for a moron like myself.
Is this essentially the same as what you all got? (zombie, OSCAR, anyone..)