It's really good to see you back with us again. I was wondering where you got to and 'lo and behold, here you are!
I was just reading about felting (also more accurately called "fulling") in Claire Crompton's "The Knitter's Bible". It has an excellent article on the process itself and some wonderful pictures that show a properly fulled piece and one that's gone too far over into nothing but a tangled, matted mess.
I was thinking that slipper socks would be a great candidate for it, especially since there's so much extra warmth once the process is done. And I'm sure a lot of craft stores have non-slip bottoms that you could apply to avoid accidents. In fact, in the latest Herrschner's catalog I saw some liquid "rubber" and some great templates in the shape of cat's paws, stars, half moons and such. I'd bet that Michael's, AC Moore and/or Hobby Lobby would have something similar.
Whatever you choose to make, please keep us posted. And again -