You could build a custom one. There is a simple pulse width modulator using a 555 timer LED driver circuit I've used in the past for foot well lighting. The pulse width modulation gives you the ability to essentially dim or brighten the LEDs since lowering the voltage causes them to flicker or just switch off.
Just an idea for you to consider.
There's tons of info out there so it won't take long to find it. The 555 chip is very popular.This sounds good. I am going to find more information into the modulation