Yes, it would be completely possible to convert the pong game to use a pair of pots. We have been asked this by a number of people, and we will put it on our list of things to do. If you end up writing something that doesn't require Wii peripherals, if you send it to us, we can share it out so everyone can use it.
Do you have pictures of your setup? It sounds pretty cool.
Adam Wolf, "Wayne" of Wayne and Layne, LLC