Desperate for more Firefly episodes I turned to reading fanfics - Fan-written fiction that is often far more faithful to the original show than novels written by professionals. One such writer is Hotpoint, whose stories revolve around the Serenity crew and the family they adopt. The initial "Death or Glory" series is very reminiscent of David Drake's "Hammer's Slammers" stories in that their subject matter is sometimes armor combat in the future and in that technology is introduced and susequent use of it is kept logical and consistent.
The "Wolfpack" series describes the integration of the Serenity family with another. It is in this series that they acquire a larger transport that can dock with Serenity and push it through space. In the show we've seen Serenity dock by flipping upside-down and connecting its front belly cargo hatch to a boarding airlock. The Granite Gorge, however, has three cargo hatches - Nose bottom, nose top, and behind the conning tower - and it is to the one in the nose top that Serenity docks.
My design of the ship was constrained primarily by the docking method, relative size, and the fact that from the Gorge's cockpit one can see over the docked Serenity. Further constraints were with the propulsion method in the Firefly universe, that is, huge gimbaled jet-engine-esque units swiveling to effect vertical and forward travel, as can be seen on many of the background ships seen in spaceports where Serenity lands. See the closeups viewable at the Zoic Studios web site. While there, note the similarities between these additional background ships and the spaceliners in the new Galactica series, the sfx studio of which is also Zoic. Note, too, that there are "magic drive" propulsion systems in the Firefly universe, namely, in Jubal Early's ship, the federation interceptors seen in "The Message", and the "Hands of Blue" ship in "Ariel", all of which are more "modern" than our old transports.
Although the temptation was to build an elongated shoebox, I tried to make the design a little more interesting with a hexagonal cross-section. I started with a 1/35 scale Sherman tank bottom hull which roughly looks like very wide, squared-off horseshoe, with a floor, side-walls, and fenders out from that. I cut out most of the floor, then used it to separate the fenders. The top of the fuselage is the spindle of a roll of fax paper. Each engine is a pair of socketed beads with a styrene cylinder out the back. The rest of the Gorge is mostly just plasticard panels, Evergreen strips, and 1/72 scale tank parts.
The last design constraint was the color. In the Firefly universe bare-metal looks gray in daylight, but mottled dull bronze and copper in some of the shots. So, I air-brushed the Gorge gray, then dry-brushed two shades of tan, some blue, red, and more gray, following that up with very light gray just to bring-out the highlights. Note that in the docked shot the only thing I did to my Gorge picture to get it to match Serenity is Gamma darken it. I think it came out ok without resorting to the tedium of miniature panel lines.