Nice! In for results. I made my own high power bulbs running on a single Cree XM-L at 1000 mA using a "puck" buck driver (1/3 the maximum power this LED can handle). It's crazy bright, and I want more!
Cree has a newer LED out, and that's the XM-L2. Too bad our tail lights don't use anything bigger than a 921 bulb so I can have more surface area to play with. I really want to fit in a quad Luxeon Rebel star.
Below is the triple Luxeon Rebel star @ 600 mA:
