I have, and I built a light pretty much from what I learned from the book. It's a 4" X 13" PVC can, with 1" thick top and bottom. I built a MR-16 head out of aluminum. The battery pack is 12 Cyclon X cells, wired to give 12V at 10ah. I'll build a test tube head next. The MR-16 head was a lot of work, but the rest was easy. A test tube head would be easy, using delrin. I'm a gunsmith by trade, and I'm lucky to have a garage full of equipment. A lathe is awful handy. You could put a canister and cord assembly together without a lathe, but you gotta have one to make a head. You could buy a lighthead, and make everything else.
BTW, went to Interstate Battery and bought a 6/12V 1.5 amp charger for $30. With a full charge, a 50W EZT bulb lasts about 45 minutes. I've also tried a Solux 50W 10 degree 4700K bulb. Haven't tried it enough to form an opinion, but the Solux is certainly blue. Also have a 17 degree that I haven't tried yet.
Any questions?
Joe