That'd be a nice design addition. Anyone got some pics?
I suppose you'd have to stow a battery pack somewhere... Seems like you'd want to design a platform of some kind and use a lawnmower battery for good, strong lights.
I'd just modify the ones that are here and add a brake. That brake/sprocket hub that is sold is a pretty cool idea, that would probably give you the most space-saving. But why lights?