the spring in the radio was about 3/4 the size of a hockey puck, the generator maybe the size of a D cell. It ran a radio at decent volume (3 watts?) for 45 minutes. I guess this would be more of a pipe than a cigarette, although I'm sure the works could fit inside an x-power.
I never thought Li-Ion batteries were okay for doing actual work; they were fore transistors, ICs, LEDs, LCDs, etc. Every single brand I have shows really piss-poor performance with the batteries but my Duracell powerpack works perfectly all the time. You just need the equivalent of five of these batteries to do a good job for this work-intensive application and we are just fooling ourselves that the current batteries are okay. We may need to rethink the whole concept of why e-cigs should actually look like cigarettes.
Anyway, if anyone is handy and thinks the carbon spring generator system has merit, I suppose a little investment capital might could get scared up.