Yeah, a bluish tone is a good idea. So the engine rear will need to be either glass-water-glass-lava-"engine", or glass-water-glass-glowstone-"engine". I'd prefer to still use lava instead of glowstone; it'll keep the glow looking dynamic.
We might need a small grinder at the bottom of the water pane to deal with any squid if they start spawning in there.
For this whole build, keep in mind that although the hull shape is set in, err.. well, stone, really (
), we still have a huge area to fill in with whatever we want. To that end, I'd love to see form follow function - i.e., let's get in mechanisms we know need to be in certain places first before we fill in the rest with decks. So, the engine, docking ports, gun turret internals, and any large internal areas hinted at by the texture map all should be created first, probably followed by primary corridors and lift shafts, then the internal rail route (encased in a glass tube, remember), and then all the decks, rooms, etc.
If anyone feels like it, see about coming up with some prototype external turret designs we can look over somewhere near basecamp.
Try to keep them so they work both horizontally and vertically.
If you really feel adventurous, go measure how big the turrets are on the in-game Fenris and try to keep the turrets that size.
Bonus points if the beam turret has a hole in the center for lava to flow out of.