Massive parasitic current leak (4 amps!)

[Multibeemer]

As it says in the subject bar, our 03 4.4i has an enormous parasitic current leak.
After having the ground cable disconnected from the negative battery post for several hours, I placed a 10 watt, 1 ohm resistor between the negative battery post, and the cable that was attached to it. The voltage drop across the resistor is about 4 volts, which equates to a 4-amp current flow! I didn't even have to make the measurement to know I have a huge parasitic leak - the resistor got very hot very quickly.

So, before I spend a lot of time pulling one fuse at a time, are there some high-probability candidates for such a huge current draw I should look at? And does anyone have a favorite method for tracking down a parasitic leak? I would think finding one this big shouldn't be too difficult. Thanks.