PHArchivist -- and anyone else who's fuzzy on the details -- here's a thumbnail of what went down...
Back around 1989/90, the Art Department of TNG (well, Mike Okuda, really) had one of the people they knew make a bunch of concept models for potential new ship classes to add into the show so they could stop re-using the
Excelsior and
Grissom miniatures. This guy, Ed Miarecki, got a bunch of the AMT/ertl 1:1400 scale
Enterprise-D and 1:2500 scale
Enterprise three-ship set (but only for the -D) model kits and went to town. At least nine models were constructed, often using the bridge module from the larger kit on a saucer from the smaller to force-scale them into smaller ships of the same technological generation. One group of three similar models got picked, refined, and ultimately debuted in TNG's fourth season as the
Nebula class. The rest were set aside.
Then the fourth season premiere happened, where the
Enterprise arrived too late and found the wrecked remnants of the forty Starfleet ships (and, later retconned, some Klingon ships) that Admiral Hanson had mustered to try to stop the Borg from reaching Earth. To populate the debris field, the Art Department grabbed many of Miarecki's study models, gave them names and decals, and thoroughly, ah... "distressed" them. They also called in Greg Jein's shop (who had built the
Enterprise-C last season, and built both the
Nebula class ship and the new, smaller
Enterprise miniature for the new one coming up) to make a couple more to toss in.
Jein's ships were the
Princeton and the
Firebrand:
While Miarecki's models became the
Kyushu,
Buran,
Chekov,
Melbourne, and
Ahwahnee:
Along with these ships -- suitably trashed -- they also threw in some older concept models from the aborted "Planet of the Titans" TV movie project, the "destructed"
Enterprise saucer and secondary hull (separated) from Star Trek III, a few bits of nearly-unidentifiable debris, and a wrecked Type VII shuttlecraft from a ship of unknown class named
Liberator.
A couple years later, the pilot for Deep Space Nine showed a bit of the active battle, newly filmed, with the addition of Sisko's
Saratoga prominently featured, as well as the
Nebula-class
Bellerophon,
Ambassador-class
Yamaguchi, another re-use of the good old
Grissom miniature -- called out as the
Bonestell in the script, and a now-
Excelsior-class
Melbourne, with the same registry as the proto-
Nebula-class ship pictured above. Made even more problematic by that wrecked
Nebula-class
Melbourne ALSO being used in that sequence (seen drifting above the
Saratoga as Sisko's lifeboat launches from the shuttlebay). Since the footage of the
Excelsior-Melbourne getting taken out by the Borg was re-used for the
Roosevelt in Voyager's "Unity", I happily mentally relabel that ship appropriately and keep the
Melbourne a
Nebula.
Then there were other production issues. The script for "Emissary" called for an
Apollo-class
Gage that ended up not being in the episode and, as far as anyone can determine, was never designed or built. In "Best of Both Worlds, Part 2", Shelby was supposed to call out three of the wrecked ships she could identify on the viewscreen as the
Chekov,
Kyushu, and
Melbourne. After everything was filmed, someone higher up thought the Chekov reference was too cute and mandated a re-dub, so they went with a different Russian author and "
Tolstoy" was added in post. No model was labeled as such, and none of the models used was intended as such. As I posted above, one of the members on a forum I have been on since the late '90s knew Miarecki and saw the various kitbashes, including the ones that didn't get used in the show. One of those he decided was the
Tolstoy, and this model is based on a blueprint created by someone else from his verbal description of the kit-bash Miarecki had built.
In the end, though, my biggest frustration is that we still only have eighteen of the forty ships that were there -- in name or in model or both. I dearly want that to be filled in -- well -- at some point. I personally think this double-saucered monstrosity is engineering nonsense, but I appreciate good workmanship regardless.