if you was going to put in a hidden kill switch , what would you do?
it is a 2004 f350 4x4 diesal crewcab...

 

I've been thinking about this quite a bit myself, lately...

I'd do a starter kill switch, and instead of hiding a switch somewhere, perhaps make it run through an accessory of some sort, like the power window switch. That way, to start the truck, you have to hold the power window switch, otherwise no power to the starter.

Of course, I'd probably try to toss in a couple more variables in there, just to make it that much tougher to steal.