One product I would like to see developed more is the bicycle horn. Most commuters I see use those compact bells, because they are light, cheap and fairly elegant. Unfortunately, they are nearly useless for alerting drivers. I know there are air horns available, but I find them bulky and clumsy to use, plus you only get a few blasts before they need to be pumped up again. I'd love to see a reasonably loud electric horn with a well designed bar mount. I suspect a standard 9V battery would be sufficient as a power supply.