I made a RED LED safelight several years ago using a single 1 Watt Red Lumiled (www.luxeon.com), a resistor and a surplus wall wart. Bounced off the ceiling, it easily makes a 11x13 foot room bright enough to easily read in, while not fogging Ilford MG paper for at least 10 minutes (the limit of my testing - the paper did not fog).
With this light, my darkroom is considerably brighter than the one at a local school that uses the orange mercury vapor lights. I do prefer the orange light to the red, but this quick hack has worked so well that I've never gotten around to testing Amber LED's.
The LED resistor calculator website listed above would work well for anyone doing the same. High power LEDs will get warm, so I used a version of the LED that came mounted on a small star shaped circuit board. That board and the resistor got fastened down to a larger piece of a copper PCB, and it's been running well, warm but not uncomfortable to touch. The LED is rated for a current of 350mA, but I run it at about 300mA.