This is something I started WAY back in 2008-2009 in 2.49 when I was really first learning how to model. I took it upon myself to try and recreate this fine, shiny vessel from a famous online tutorial done by a gentleman named Treybor over on the Lightwave forums (I don't believe you can find the material for the tutorial online any longer, but Google it for more details).
The final version of this is lost to The Black, unfortunately, as the file became unreadable somehow. This is the closest version I could reconstruct from those older versions into a 2.6 .blend file. I am planning on a new version of this beauty with Blender 2.6 and the new modeling tools available. I will be releasing a finalized version of this in the near future, hopefully recovering the missing elements (landing legs, shuttles, CRUDE interior) or quickly remodeling them for a finished Serenity. Until then, I've been "Badger"ed to release this, so I shall, under CC (CC-BY-SA of course, I spent literally a year of my life on this thing, so hey... credit). If used, you must credit the model to me, or if modified and/or re-distributed under CC-BY-SA, original credit for the model to yours truly.
The file contains the ship as you see it in the image(s). 2.5 million verts, about 2 million faces, so you need some power for this. The ship components are on seperate layers, and I'm not sure if I set and labeled a naming convention for the individual objects. Feel free to texture, modify and use the model, it does constitute "fan art," it is not an exact duplicate of Serenity, but it is big-damn-heroes close. So don't push it by trying to use it for anything "commercial" where you and I would end up getting sued by FOX, Ok? In fact I'd like to see what some ol' fashioned Browncoat will do with this, if you'd like to share your images with me for a compilation, I'll include my contact info in the .zip archive.
Blender Artists Forum
(Update: Cleaned up and ordered the layers, object names and parented everything so it is less confusing, anyway)