I'm not understanding how you could have measured the battery current drain at 75 m.a., yet removing fuses didn't isolate the circuit that is responsible. If this were true, then you must have something connected to the battery that does not go through the fuse box. This is a real no-no. I'd suggest removing the fuses again while watching the current draw with an ammeter, to make sure you didn't overlook the correct fuse. And if it is really true that removing fuses does not stop the current draw, then look for something that is connected to the battery but does not go through the fuse box. For example, is there any half-vast stereo or burglar alarm installation involved?