I think it would be neat if the wooden sections of buildings and airships could be painted, similar to the way you can "paint" iron over them. There could be a "Paint" tab on the building screen next to "Modules," "Armor," and "Decals."
The paint would show on the outside, but not on the inside.
NPC fleets could have a certain chance (50%?) that the ships will have paint. The paint could be based on the nation's coat of arms.
Yep, sounds good. Cheapest way is to just add a tint to the sprite drawing, though it may be better to decompose the metal and wood parts. I'll experiment. :D
Paint is in and will be available in version 4.1:
It actually didn't occur to me that materials other than wood should totally be paintable as well, glad you thought of that. Are you going to be giving the default ships paint, or is that screenshot just an example?