The good folks over at Velo Orange have sourced a new switchable dyno hub. It has the same output (3W) as other dyno hubs, but thanks to a new clutch plate, you can disengage the magnetic drag that is used to generate power. During the day you have a wheel like any other, with normal rolling resistance, but once that sun heads to bed, you can spin the clutch and light your way home.
It comes in high polished aluminum with either a 32h or 36h drilling. Be willing to part with $130 to add this to your bike.