'57 T-Bird draining battery

[blucar]

Something in my '57 T-Bird is draining the battery. I have a battery disconnect switch that is attached to the negative battery post and cable. If I forget to turn the switch off, the battery will be deader than dead in the morning.
I have tracked all of the circuits looking for something that is going to ground.. I thought that I found the problem when I found that the alarm appeared to be draining voltage... I checked the alarm to make sure the switch was in the off position, it was, but there was still voltage draw. I disconnected all of the leads to the alarm, there were three.. Still had voltage draw.
Checking the brake light switch revealed a minor voltage draw.. Replaced same with a new switch.
I have checked every accessory, radio, heater, power windows, and power seat for voltage draw.... disconnecting all of the accessories does not eliminate the power draw.
With the negative switch turned on, and all accessories turned off, disconnecting the positive cable will produce a noticeable spark between the cable and the battery post.. Checking the voltage will show a draw of 12.6 volts, which indicates a major drain on the battery.
Reading through my Motors Manual for electrical trouble shooting, I noted that Ford used an internally grounded generator in '57..... Could the generator be going to ground??
The regulator is a brand new unit...
Any ideas as to what is causing the problem....Bill