This is the current state of my hand built LED on camera light. I would have posted some build pics, but I just didn’t think to take them. I do think that those out there who would be inclined to build such a thing would find it pretty simple.
Basically, I used a Luxeon Endor Star LED, a Luxdrive Buckpuck, a pot, and a switch. Currently, there is a battery holder inside with eight AA batteries. I intend to add a jack for an external battery pack. It does run quite a while on the AA batts, especially if you have it dimmed a bit.
The gray squares are simply velcro. I made a simple diffuser out of frosted plastic much like what you’d find in a “trapper-keeper”. It works fairly well, and doesn’t cost all that much light output. These emitters are extremenly bright, and you do not want to look at them directly when there under full power. In fact, they’re classed as class 2 lasers for this reason.
The star is quite simply bolted to the aluminum housing, which is an off the shelf “Bud box”. It’s more than sufficient to sink away the heat from the Luxeon. There’s a diffuser optic glued to the unit as well. You definitely want to solder up the star before you mount it. Otherwise, the heat from your iron will be pulled away by the heat transfer to the chassis.
Interestingly, this is actually a “warm white” LED. It more closely matches the color temperature of incandescent lighting than those blue/white high output LED’s most often used. While I’ve not actually measured the output, I would say it’s close to a 20 watt halogen.