I would love to be able to get a ready-made LED replacement headlight to match the technology of the rest of the bike, but for the DIY-ers here, someone on the Zero forums modified his stock headlight (essentially identical to our Empulse headlights) to use a powerful LED source.
http://electricmotorcycleforum.com/boards/index.php?topic=3431.0It looks very nice (or will once he seals the ragged gap he cut into the existing lens).
The Cree lamp he used produces a healthy 1700 lumens and is available with CRI (Color Rendering Index, a spec which most LED lamps ignore and produce a very unusefully bright light) of over 90. Personally I'm a big fan of using a more natural light even for headlights because it is too easy to mistake quantity for quality and a bright light with a poor CRI will make it harder to see some objects than a dimmer light with a fuller spectrum.