Check out these Lights.
24v, 5 year bulb life, Low power, and Low heat. Tons of options, but very pricey.
Quote from a member of another site.
I have their sheet right here!!! They are also expected to last 5 years (the bulbs), and **** that is gonna be a lot of bulbs to change!!! Here are the show prices:
13" $449 75 watt
24" $799 150 watt
36" $1,229 225 watt
48" $1,499 300 watt
60" $1,799 375 wat
72" $1,999 450 watt
and it is an extra $139 for the Control Module Adder which lets you hook it up to your computer or something, so you can download stuff like the exact color of light from 6.5K-20K, and light patterns throughout the day. Kind of pricey!!!
There is also a Metal Halide starter that hooks to your computer that monitors the light & bulbs. It will let you know when your light is going bad, and tell you what you light output is, and you can even monitor your lights remotely from the web.
once they become more popular, i'm sure prices will come down.