replacing a projector bulb with leds

[mikeselectricstuff]

DLP projectors (apart from very high-end cinema types which have 3 DLPs) have a monchome DLP and are switched sequentially, usually with a colour wheel. The actual modulation by the DLP is done by fast pulse-width modulation, as the micromirror positions are effectively either on or off. 

In that case using an RGB LED will automatically incr4ease the efficiency by a factor of three and the LEDs can be derated as the duty cycle is 33.33%.

Yes, however it's complicated by the need for optics to make all 3 LEDs project from the same place, to avoid misregistration.
Here are some pics of the insides of a LED pico projector http://techon.nikkeibp.co.jp/english/NEWS_EN/20081226/163392/