I used to have what I called the "safe". All it was a six by four by eight feet high steel walled room. The door was two by two tubing with a deadbolt lock. The sheeting was all eighth inch plate.
One of the things that always bothers me is how thieves are looking for the quick pawnable stuff, saws, drills, grinders, etc. Of course if it wasn't for so many short sighted idiots that don't care or want to know if their bargain is hot we wouldn't have so many thieves.
Of course the only justice is the thief now knows where there's some stuff if he--she is in a bind for bucks down the line, due to whom doo is due you might say.
The room doesn't have to welded up solid. Heck you could use a wood frame and carriage bolts to put it together. What you're after is getting in is going to take time and hopefully effort. Thieves are not much on hard work, remember that.
I've also had some pleasure not using conventional locks to slow down the thief. Stuff like push then pull catches etc.
I used to have a compartment on a truck that had a slide latch that looked like a twist type. For fun I'd point the compartment out to a newbie and then tell them it was an IQ test. I told them everyone started off with a hundred and fifty seconds to open it and I could usually be right on with their IQ with the actual seconds it took.
One time I had a job in my hand when the doctor was admiring the truck. I pointed out the compartment and gave him my spiel. He went for it.
He was a bald man with fair skin. As he fought the latch I watched the red come up from his collar, past his ears, until his pate was like the advertisement in front of a house of ill repute. /forums/images/graemlins/blush.gif
I didn't get that job. But I'm not entirely stupid. I only pulled that on nonpaying types after that. /forums/images/graemlins/grin.gif