Ok, some good news!
I called the American Consulate in Marseille (and actually got a hold of a human) about the extrait de casier judiciaire, and while they cannot issue one of those exactly, they can give me a sworn, stamped and official paper signed by the Consul General that is equal to it. And it only costs $30.
I'm getting closer!
Next Tuesday I have an appointment after lunch to get said document.
It's a 3 hour train journey each way plus I have about four hours to kill in Marseille, so it's going to be a long day.
Any suggestions of things to do in Marseille?
My dossier will be ready to send off once I have this paper. Yahoo!
French Citizenship, here I come!