I was tempted by these but the run time of an hour and the fact that some people seem to be waiting up to 6 weeks for delivery put me off slightly. Apart from that, they do look pretty amazing.
I've been lurking the forum for a while, hello. I just moved to Cardiff from Glasgow a couple of months ago and started riding fixed down here. I've noticed quite a few fixed/single speed riders about the city.
There was an article on Core77 about this a couple of weeks ago which explains it in a bit more detail:
http://www.core77.com/blog/transportation/project_aura_bike_safety_lighting_system_19349.asp