Pretty darn Vapin, but I'd go for simplicity, and thus affordability (and volume volume volume).
Just make them to fit a boge 3Ohm, all plastic with rubber grommets in the ends. Simple
Carto-
tanks are the obvious "next-step" in the evolution of the e-cig. Make these rugged, cheap, and plentiful, and I bet they would benefit the whole e-cig endeavor.
Another Idea: Line up eight or ten boges in a bench vice and go at them with a hacksaw from both sides... you could slot a few hundred in an hour or two... sell them for a buck more than the boge cost you... hell, I might retire.