The admins at Bitcointalk should have several IP addresses from Satoshi, because the IPs are saved in the logs. They are in the Database somewhere!
Why not revealing them?
What if the Satoshi in bitcointalk.org is not the real satoshi? I have my own theory because I think there is a possibility that Satoshi username can made by anyone of us. If it will become real, Satoshi will be appeared and tell us that he is the owner of that username. Anyway, we don't need to investigate him anymore because he already let us use his invention.