Sculpey actually makes eraser clay. My daughter's BFF got some for her birthday. They come in nice, bright colors. http://www.sculpey.com/Products/products_poly_eraserclay.htm
I made this little dude (about 2 inches) a while back with Fimo Classic, which is firmer than super sculpey. It definitely bakes up hard, but I have a feeling it took surface details better than a softer clay would. I guess if you want to have a figure with an eraser feel, you would want to use the eraser clay.