[fastraxsg]

I've run my trunk mounted battery with a negative side ground switch for serveral years. It has a short lead from the negative terminal to the switch and another short lead to the frame. I have a large marine battery box with a small sealed cell in the box. I mounted the switch on the side of the box so the terminals are mounted in the box and the battery is fixed in the box so it won't slide around. If the box comes loose, the terminals won't short out to anything even if it turns turtle on me. Having the switch in the trunk is like a simple anti-theft device but can not be reached in case of an accident. Might consider a second switch on the positive side in the cockpit where you can reach it in case of an accident.
Don't buy cheap switchs for these.
For another simple anti-theft device, try installing a dimmer switch located some where under the carpet that cuts out the primary lead to the coil. Read that one in StreetRodder Magzine.