Remote Battery Disconnect on ground side?

I want to put a remote battery disconnect in Dad's Duster while I'm moving the battery to the trunk.
In his 69 Dart I bought a unit that works perfectly but haven't been able to find it again.
What would happen if you used a Ford solenoid directly off the ground terminal and from the other side of the solenoid to a ground point.
Then run a small ground wire from the battery to a remote toggle switch...leaving the switch back to the small terminal on the solenoid basically duplicating what is done with the hot wire in a starter installation...
Any reason this doesn't work???
It would be cheap and I don't need a mechanical disconnect for racing purposes anyway...
All I'm really looking to do is toss a switch after I shut the car off that disconnects the battery completely...I'm not worried about isolating the alternator while doing this...
Thoughts???

Just make sure the relay is rated for continuous duty with a high enough amperage rating, not just spot duty like a starter solenoid. make sure to fuse the trigger wire at the battery.
Doug

Do it right. This says for GM but it works on anything. It cured my hot start problem and made the car NHRA legal. http://madelectrical.com/catalog/st-1.shtml