I thought about that sensor but with a bulb installed it would get too close to my head. The door jamb switch is a novel idea but not sure i want to run any wiring and figure out how to connect it to 110v.
Found this just now http://www.amazon.com/dp/B0157RTZC4?psc=1 seems it'll give me a bit more headroom.
Rather than searching for motion detectors, a few years ago, I found a much larger selection when I searched for "occupancy sensor." Seems this term is applied more often to indoor situations.
I don't mind false positives - I don't care if the lights turn on. I have false negatives - flapping my arms like mad to get the lights to turn back on.