All I did on my truck was installed 4 identical on-off-on toggle switches in the dash;one had to be up,next one had to be center,next had to be up,last one had to be down to complete the ignition circuit. I'd just flip all of 'em down when I parked it.Being marked cab markers,driving lights,dome light,and electric fuel pump,who'd take the time to figure out the combination? It was hard to bypass because the switches were boxed in with a panel that went from the lower edge of the dash to the firewall. I connected the firewall end with a hinge attached on the inside,and used two tool box lock cylinders to attach the dashboard end.
I figured if they want it bad enough to run that gauntlet,they've earned it. Seems to me,the whole key is surprise-throw something at 'em they haven't seen or don't know about. They have a time crunch to deal with,so anything you do that makes 'em spend a lot of time on getting your truck will cause 'em to give up and look for easier pickings. They don't want to get caught in the middle of trying to figure out your puzzle.
A buddy wired the fuel pump on his 50 chev.3100 through the parklights.If somebody took it in daylight,no fuel pump;if the took it at night,no fuel pump.If they decide to be cool and go cruising at dusk,well,maybe.
Another idea I saw used is like a knife switch mounted inside the bottom of the dash,with a small hole in the sheetmetal,where you'd insert a steel pin.Without the pin,no power.(Also works as a kill switch) Any number of different ways to screw up a truck thief. Be creative!
Speed
BTW-my favorite way is the silent alarm with mercury switches.Somebody messes with your truck-it pages you,so you can go watch them work while you wait for the cops to arrive.
Added benefit-I NEVER drove it while intoxicated,and not always by choice.
