[Zynice]

Hey, I actually had a similiar issue to this recently. Two things I would check in specific. The fuse coming out the battery positive. If you have a multimeter id check the voltage on the battery both when it was in the off position and the on position. If it drops to zero with the key on, could either be a faulty battery (was one of my issues) or there was a short in the ground somewhere. Possibly if you have another battery laying around in a car or something. With jumper cables, could try putting the positive on the positive, negative on the other battery, negative grounded out. If you get power then probably just a bad battery. If nothing probably a short in the ground. Through trial and error found that if the bike kicks over and everything works properly(turn signals etc), its more than likely a bad battery than a bad ground wire somewhere.