I don't understand the workings behind the signing process but, to me, it looks like you can write a program that can take any address and your own message to create a signature so that you can pretend it's your address.

We really should close this down as early as possible as there will be new stragglers slowly trickling in who will want to pay after a few days. There are other group buys going and someone could create another one. If Arklan likes doing this he can start a second group buy.