Strange, I ran across this website while searching for info on HIDs. Their 4 position 4100-10000k temperature switch seems kind of unrealistic, but seems interesting.

Go to http://www.hidkits.com

 

As an electrical engineer it is technically possible. The voltage for lamps depends upon the gap between the electrodes in the lamp further apart=more voltage needed to fire the lamp. The balast is actually a fairly simple circuit that uses switching circuitry with eletrical components to determine the voltage that the balast pumps the 12b V input voltage up to.