Just thought i'd post about this motion-detecting LED light, which only turns on when the seat is open at night. It's a tiny thing that fits perfectly under the seat of my People 250, and it lights up the entire met-in box from above. Recharges with USB if you use rechargeable batteries. Attaches with velcro, so it can be used as a work light off the bike. It's $6 on Ebay - search for "USB infrared LED light".
Cheers