Yeah, you're right. I was browsing through my videos (complete 2nd Berlin show and half of the Munich show) and the first time the backdrop changes from that ambient structures to the cell-like curtain is after Sehnsucht before Asche zu Asche. The cells stays until after Mein Teil where a industrial/factory looking curtain is introduced that stays until the end of the show (with the added propeller for the encore Mein Herz brennt).
So "Teppich" propably means backdrop. I was just asking since this is the first time I've heard/seen the backdrop being refered to as "Teppich" in German.
EDIT: Shit, shouldn't have dived too deep into these videos. Makes me really want to see them again!
Hopefully they'll have a few closing shows in Europe booked. I'm not too fancy for a festival gig, but I'd definately drive the way to Berlin again.