I will being doing something similar with a GU10 tracklight. The GU10 bulbs are 110V halogen and the tracklight is dimable using a standard wall dimmer. But the project will replace the 4 bulbs with 3W RGB LEDs that will be arduino controlled. But to do this, I have to gut each of the housings and run wires in the track to the arduino that will be housed in the ceiling and powered by a 5V transformer. The arduino will then control the colors/intensity of the bulbs by PWM signals to MOSFETs that power the LEDs.
Is this similar or are you starting with something different?