I'd be very hesitant to go without a light. I always carry a small headlamp (Black Diamond Gizmo, currently, but I've also used a Princeton Tec Scout and Petzl Zipka), and use it pretty much every night.

Have you looked at the Princeton Tec Pilot light? It's small, weighs less than an ounce, clips onto a shoulder strap (or leave the clip behind and save a fraction of an ounce), and provides plenty of light for camp chores or the inside of a tent - maybe even enough to walk a trail on a dark night, in a pinch. I used to carry it as a backup light - hey, now that I think of it, maybe I should carry it instead of a headlamp?!