One place to start like they said is the fuse box. Unplug everything that you've wired in that isn't necessary to drive and check overnight like before. I think you said before you've hooked up most everything...so what else have you hooked up to your power?
If you have a voltmeter, you might be able to do it quicker than overnight. Hook it up across the battery. With the car off, it should be stable. If it's draining (even slowly), you should be able to see it if your meter reads enough decimal places (3 should be plenty). Start unhooking suspect wires until it stops draining.
