There is an eGo model that has an LED that will display the battery life. Some VV/VW
devices will do that (provari, darwin, lavatube, vmax, zmax, the new eGo VV, etc). I think, with the exception of the eGo models mentioned above, most devices that have this functionality are $50+. Of course you aren't paying that much just because of that. To be honest, I wonder if original designers over-looked a good feature, or perhaps it rose cost too much, or perhaps it rose the failure rate of the
device higher, or maybe even size was a factor in not including battery indicators.