I am running a GURPS campaign set in the Firefly universe with the intent of telling the same kinds of stories as seen on the show. Thus, the PCs are a sort of grab-bag collection of people on a small freighter trying to make their way in the Verse. Since Serenity plays such a big part in the show, I felt like we needed a way for the ship to really feel present. I decided that big 24x36 poster-sized deck plans would do the trick.
I did a ton of preliminary sketches trying to decide what shape the ship should have from the outside and how things should be laid out on the inside; decided which rooms are required and why you might put them next to which other rooms, etc. I wanted the ship to feel sort of like Serenity, so I decided that the Jackrabbit class was made by a competing manufacturer as a sort of me-too design to the Firefly class. The Mark 2 Jackrabbit (seen here) came out somewhat after the Mark 3 Firefly (of which Serenity is an example) and you can see some common design decisions/plagiarism. Overall, though, the Jackrabbit is a smaller vessel; much more compact.
I started out in Google Sketch-Up and made several passes, but eventually had the whole ship modeled out to a level of detail that would look good (I think) on a map. So then I exported a bunch of images of the model all cut up and layered them together in the GIMP. I did all the icons and font stuff in the GIMP, as well. The Chinese is probably very poor and is courtesy of Google Translate.
In any case, the maps:
I painted one wall of the room where we play with magnetic paint and hold these and Quantum Mechanix's Map of the Verse to it with neodymium magnets so we can take them down and put them up at will without destroying them or the wall with tacks. They turned out WAY better than I'd hoped. These have a couple of touches of color, but they're printed in black-and-white (since I was using the plotter at my wife's office, I thought asking for color ink would be a bit much of an indulgence).
So... whatcha think? Feel free to ask any questions and whatall. I spent... a significant amount of free time on this project.