Sounds like a short to me. Simply unhooking accessories might not be enough. Did you try unhooking wires that feed the power to the different accessories, such as at the junctions under the hood?
A test I usually try is the light circuits. I prefer to use a buzzer style tester, but an ohm meter will work. Disconnect the lamp wires at the switches and remove the bulbs, you need the circuits isolated. You can do this one at a time or all at once, depends on your comfort level for re-assembly. Then check between each bulb socket and ground, and follow the wire to the switch, wiggling everywhere it goes through any clamps and holes. This is where the buzzer comes in handy, you can hook it up and leave it alone while you're under the vehicle. Most shorts that I have found have been where the harness frot the tail lamps go through the retainer clips.
