That is innovative! Could you share pics of your engineering? Also how do you power it? I'd love to do this project.
Main problem is, that I went a little bit tricky with it, I didn't just use White LEDs, but I got hold of some RGB Superbrights, so that I could change the colours if I wanted too (I was mainly thinking, at the time, that I'd use it with my Lensbaby and/or film for some lomo-esque lo-fi shots.)
First incarnation was using 4 potentiometers, 1 for each colour and 1 for brightness. Worked well at prototype stage but the pcbs were so big (using normal through-hole resistors etc) that I could only get 4-6 LEDs in each ring, so wasn't actually too bright. If i'd designed a proper surface-mount PCB then I could have gotten a lot more LEDs in.
Instead, I'm now trying for a digitally-controlled version, using an Arduino board (freetronics even sell a controllable RGB LED module, although it's probably not bright enough so I'll use the superbright 5mm ones from the first incarnation. (Long term project is to write an app with a colour wheel, click the mouse on the colour wheel and the LEDs will change to that colour. It'll probably never happen).
But then work and buying a house and whatnot got in the way, so it's sort of on permanent hiatus, I'll resurrect in in a few months maybe when I get time (and the new house). But I can probably share shots of it this weekend.
The first ones were powered by either a 6V Sealed Lead Acid battery, or from a DC wall-charger from any number of transformers i've got floating around. The Arduino-based one I did have in mind to power from USB, once i get to that stage at least...
Correct me if I'm wrong, but wouldn't LED's be continuous light, not a 'flash'? So would it be more correct to say a ring LED light? Or are there actual LEDs that are used to 'flash' like a traditional ring/speedlite flash?
AFAIK there's both. The reason I started building my own (besides the fact that that's what I do, even though probably more expensive than ebay), is that they all seemed to be 'flashes', and as I said, I prefer monolights. If you count my attempts as a monolight version, then there's definitely at least one of each type in the world...