The technicalities of an actual lightship model aside, the thought occurred to me that what you needed there is clearly a neon tube substitute and it would seem Electroluminescent wire (here on out just EL wire) would seen to fit the bill nicely. I've seen it used on clothing a lot (fan costuming at cons mainly) and they do sell the stuff for auto detailing.
The question I have, because I search the area for discussion about this and couldn't find it, has anybody used it for modeling. I figure if it's good for clothes, it should have reasonably low power requirements and a relatively low heat signature. No?
It would seem to be a better lighting alternative for any area that needs a length of light rather than point sources.