This HID theft is very bothering indeed. I can think of 2 possible home made "solutions".

One would be to rig some sort of smoke device or flare to the hood via a cable(probably no thief would look for an extra cable in the dark). When the hood is opened, it could activate the flare or smoke device , pulling a pin or what not. It would be quite hard to ignore an orange cloud of smoke coming from a car.

The 2nd approach I created a couple years ago, after getting the ideal off of the Discovery channel. It involves using a nine volt battery. The on/off state of the battery would be triggered by a hood pin / switch. In the on state power would flow to a silicone diode (found at Radio Shack, would have to look up the exact specs again). The diode would have a firework wick (most fireworks legal in CT) wrapped around it with a match head, then dipped in wax. The diode would heat up enough to melt wax, light the match head, and in turn, light the wick. I had this setup in a rear wheel well, and worked too well (forgot to turn off sometimes).
I am going to look into a home made solution more after the New Year. I’ll post anything that works! Please add ideas!!!

 

Im still trying to cad up and get someone to make a forged steel plate that will go over the whole tab and side of it preventing them from even attempting to cut it.

Problem is getting the cad 100% right and then getting someone to make it for a reasonable cost.

Dixit

 

they'll just jack the wiring and ballasts...you'll be left with a shell and be forced to by a new set anyway

 

How can you jack the wiring and ballast? The ballast is all the way on the bottom of the assembly and cannot be removed unless the headlights are removed from the vehicle.

If you block the ability to remove the lights then this is solved. Unless they want to sit there with a recip saw and cut through 40% of the light just to get the ballast and the bulb. Which if they did, I guess they really in need of it. With the forged plate, they cant do nothing but sit there and think, DAMN!. This ensures people wont be left with just the tabs of their headlight assemblys.