| Ok, this may be a dumb idea and kinda tedious, and I'm not even sure if it'll work, but here's what I'd try: when the battery is charged up, and the negative cable is disconnected, touch the cable to the negative post. You see a small spark, right? That spark means that something is drawing power. Then go and unplug all the fuses. Put one of them back in. Then touch the negative wire to the post. Does it spark? If it does, then something that runs through that fuse is drawing power. Continue this process for each fuse. Most of them shouldn't spark since there shouldn't be anyting drawing power when the car's not running (with the exception of the hood light, and a small amount of current for the CD player and the ECM memory). This way you can begin to isolate what system the short is in by seeing which fuse it is run through. Then find out what components that fuse has power to. Uh, if you take out all the fuses, and it still sparks, then obviously I have no idea what I'm talking about here, and you might not want to waste your time trying this. Oh, yeah, you also might want to make note of where all the fuses go, I know they're labeled and all, but just in case... | 
