Here's my dream LED light:
>
>- dimmable from 0-100% with no change in colour temp (ultimately I'd like to
>build in a remote control so I can change dim the light whilst I'm looking
>through the viewfinder on my camera)
>- cheap!
>- highly efficient
>- stable and predictable colour temperature
Colour temperature's one thing; what about the heat problem? You'll be no doubt bunching these hi-output LEDs together in some sort of reflective enclosure and they're bound to get very hot when running at any useful level of brightness. Plus the hotter they get, the more current they tend to pass (if not limited) which makes them hotter still and makes for the difficulty in setting a constant level of brightness. Can they really cope with the intensity of being used closely bunched together even if you can control the brightness satisfactorily?