This shows three scratchbuilts (in order or building from left) and a Gamescience metal D-7.  All are hand painted including markings, and date in the early '90's.

Part of my philosophy is, "Screw the canon! It's all made up anyway, so I can bloody well make up my own ships!" SF modeling is my relief from the rivet counting I do when I'm modeling historical subjects. Folks who are really into the canon are invited to imagine my stuff is sort of like Luftwaffe '46.

My scratchbuilt Klingon ships have a similar layout to the D-7, and the same sort of warp nacelles, same or similar impulse deck, and similar command hull with superstructure. All have engine glow under the main hull. (Really hot radiators?) The bases are based on the ones DML used for the aircraft in their 1/700 scale Modern Seapower Series kits.

The leftmost is a lightweight, made from single thickness styrene sheet (.020" maybe) with the teardrop part of the command hull made of Sculpey.  Overall dimensions are similar to the D-7, but it's got smaller warp nacelles. It's some type of scout. Its captain would be suicidal to try to slug it out with a Federation cruiser, but he could probably outrun it.

Next one is a real hotrod, which is a direct design evolution from my scout. It and the next are built up with layers of sheet styrene, bits of stretched sprue, and Sculpey. Much lighter and faster than a D-7, it's as heavily armed. Its weakness is it can't take much damage, sort of like HMS Hood. If I knew a Klingon word for "falcon," that would be the class name. Features include elongated command hull, a skeletal main hull, and the red external plumbing around the command hull as seen on the Bird of Prey, which I interpret as the cloaking device. I drilled windows into the command hull, which I regret. I've been itching to scratchbuild another one of these in scale with the AMT D-7.

The last scratchbuild was actually an attempt to do a movie D-7, without benefit of drawings or video capture. (I said early '90's, remember?) The parts count is 72 as I recall. Each warp nacelle is 13 pieces. The sensor dome stands on a metal wire framework, like a water tower. Compared to the Gamescience D-7, it's obviously much leaner and more rakish. Well, maybe it's a movie D-6.

The Gamescience D-7 is painted using the same shade of Humbrol as the scout. (My choice of color also follows the above described philosophy.) As on the scratchbuilds, I added two droplets of Micro Krystal-Kleer to form the lenses on top of the bean-shaped structure atop the command hull. It seems overly bulky to me, especially the main hull and warp nacelles, but I haven't compared it to any drawings. Perhaps it's a matter of ease of casting.

Starboard

Front left

Aft

Top left