On edit: I have no idea how I got the emitters wrong, I'm using XRE emitters because I figured these weren't going to be my last lights and they were easier and cheaper for now.
I hooked my Cree XRE R2's up to a variable power supply and I'm still seeing spots. I also got some XRE red LEDs for the rear. Those are also pretty bright. Don't know that they bin those for brightness though.
I'm building a dyno lighting system. I have one of the Shimano hub dynos with a Shimano incandescent light that doesn't quite cut it.