I'll check behind the fuse box to see if wires are touching, this is the second fuse that went up in flames. Do you think the wires in the trunk hinge could cause this problem?
you should be able to remove fuse and measure 12 volts on one side, and nothing on the other side. The side with 0 should not read a direct short to ground, but would probably require removing the lamps in the brake lights to confirm this. I would check the lamp sockets first, removing them, and hitting the brakes to see if the fuse blows, if it does you probably have a dead short in the harness, and yes possibly in the trunk harness.