My led man also had some Luxeon leds and some lower cost substitutes - heat is a big problem for the high power leds - just look at the specs. The sample was mounted to a special aluminium substrate for heatsinking. I dare say this stuff is not cheap - it was about 0.5mm thick aluminium with a thin insulating layer and the usual etched copper on top. Like most heat related issues - it mainly comes down to surface area and air flow. Erik's use of multilayer pcbs would have reasonably good heatsinking properties along with the conservative current would mean he would have a good expected lifespan for the leds.

Jan - the component cost on my display decreased when I went to discrete leds! This will be offset for the increased labour for assembly though! The discrete leds are *MUCH* brighter so I can run less current.

Payam - remember to read the specs carefully - nothing's free in this life! In any extended temperature range application - check all your components - electrolytics are another killer, even if you use 105degree parts, the life is severely shortened in higher temperatures. NipponChemiCon have some great info and tables that give an insight into this.