You may be having issues finding a dimmable LED fixture due to patents Color Kinetics was awarded. They have many patents on things such as pulse width modulation (blinking LEDs to simulate dimming) and they love to protect them. Going after Chinese companies it a lot harder, but they often go after companies in the US selling such fixtures. This is why the LED fixtures we distribute actually get dimmer by lowering the power provided to each LED. But, our stuff does color mixing so that's not what you really want, plus it makes it a lot more expensive.

Might I suggest looking at a dimmable flourescent such as this? It will probably cheaper since it's already dimmable out of the box, and it won't get as hot as an incandescent lamp. It may not get as dim as you want though. I think their range of brightness is pretty limited. This one claims to go from 100% to 10%. Maybe they got better from the one I have...