Clare, have you visited Second Life? If so, you can find me there and we can talk. I am Alexsis Kamala in Second Life. If you haven't visited, I can help you get started. It's a lot of fun and you can meet some great people there. I have made contacts with several colleges and with several education groups that meet there. Let me know if you would like to join me.
I got your post on the Educator's PLN. I know this won't help you now, but I know of a guy who is speaking at NYU in November that is talking about "seeing" numbers as large at 10 000. He talks about being able to combine (add and subtract) these numbers by just looking at them. He works mostly in Second Life, a virtual 3D world. His talk will be broadcast from Second Life into the conference center at NYU. Everyone is invited to attend by going into Second Life. It should be very interesting. He claims to be able to teach even very young children to see this math. He is attempting to totally change the way we teach math.
I can give you more information later as I get it if you want.