There are quite a few of these stop motion animations on youtube by this guy PES, this one is really awesome. It just goes to show how far you can go without using clay, and still make an incredible video. The sound goes a long way, and the textures of the different materials found really make for interesting and fantastic animation.
I've been carving tiny pieces of furniture out of foam... let me tell you what... more difficult than I imagined! I'm thinking about finding some of that foam you stick fake flowers into and seeing if that melts with acetone. I would think it would, and if I'm recalling the texture correctly, it might be easier to carve into. We shall see!