Have you tried making them? This was discussed a couple of years ago and might be worth a search. You can buy the various component parts and the fibre cable. I've not tried it but it sounded simple......
Yeah, I've given that some thought but I learned from an engineer friend of mine who made his own and then went on a liveaboard trip to the Galapagos only to be struggling with inconsistent results the whole time. The trouble is that when you go somewhere for a week or two of diving, you value consistency. Were I to live in Florida let's say and dive whenever I wanted to I'd probably make my own and enjoy the challenge of perfecting them. But I'm hoping this is one less thing to worry about.