I built a light using 54 of this
http://www.superbrightleds.com/leds/w4_specs.htm. It's powered from a 7.2 volt power supply, with each set of two LED's wired in series. It works pretty well.
I want to try to make a bigger one, something I would love to add is the ability to dim the lights, does anyone know how to go about doing that?
Also, what do you think of these LED's a white 5600 kelvin color temperature is my ultimate goal. But $1.50 a bulb is pretty pricey.
-happymaan