I gave the Nifty Xtreme mats a shot... they looked outstanding in the Performance Products catalogue, so I took a chance and ordered them. They were not soft rubber like regular flat mats, but hard (ridged, but still flexible) formed rubber, about a 1/4" thick and smooth except for a light texture. They're custom-contoured to the shape of the floorboards, shaped like a pan with nice tall sides. Are these what you're talking about? They sure looked great.
Unfortunately, the problem I had with these mats is that the bottom of the "pan" did not touch the floorboard, and since they are pans they would not conform and lat flat. Whenever you stepped on either one of them, the tall sides wanted to bend, or "fold" like a cheap piece of cardboard.
I sure liked the concept... I wish they would have worked out.