Heh, I found those too, and they look like a possibility. I don't know why, though, but I get this feeling like it might not work. It's difficult to get an idea of how wide the ribs or the openings are, and so it seems like they'd be walking mostly on surfaces that didn't remove any litter at all.

It would be worth a shot, but it's pretty expensive. Plus it's actually way too long for my purposes, and I question whether my jigsaw (my one power tool) could get through that material...