http://reviews.mtbr.com/lights-shoot...r-measurements
Current and past Shootout light measurements. The chart given is from 2008. Pretty much every LED model in that chart has been superseded at least once over. That being said, it took four years for LED lights to catch up, but there's a lot of lights now that are measurably brighter according to the tests (wish they used an integrating sphere...). Its still impressive how cheap the HID lights are in comparison, though if I'm going to be dropping $400 on a light I'd try building my own first in any case.
That last site is pretty impressive. I kinda want to take up motorcycling now.