Here's a 4+ year old product with some dissatisfied customers: Go Brightz LED Bicycle Light.

I mention it because this is one of the few products tailored for active side lighting mounted on bicycle tubes: they give you a row of amber LEDs mounted in a package with a AAA battery holder and holes to zip tie it to the sides of your down tube. It would be nice if some cycling company designed a more elegant, updated version of these.