Chains and belts, caliper brakes, shocks, are all maintenance pain. Cam shafts are cheap to maintain but require a bike that is built around a shaft drive - they're not compatible with a standard frame setup.
Put all the electronics in a detachable pod on the handlebars. Light, horn, camera - all there. You can easily pop it off and take it with you.
Edit: if I were crazy enough for a hardware Kickstarter, an all-singing electronics pod would be it. A long-necked bike light with yellow leds down the side for side visibility and a pair of buttons for horns - a quiet pedestrian chime and an earsplitting horn guaranteed to cause hearing damage if used carelessly.