I have to say I'm impressed, and I hope the next version of beam lighting will be this one.
Having said this, I also have to say that I'm slightly disappointed that the light hitting the hull of the ships is not exactly aligned with the beam itself, it seems that the light source is too far away from the hull itself, and the end result seems more like a reflection of a somewhat distant light, rather than the beam's light itself.
When I read your explanation, I thought, "Great, someone made a nice review of id's cheat on QuakeGL's missiles light (spheres)", but after seeing the videos, I see that by "tube" you mean something different.
So could someone explain to me what is geometrically happening within "light tubes"?
EDIT: And perhaps make it a little less "subtle"?