Sometime during the 1980s or early 1990s, when I had money and could afford cable, I stopped on the public access channel because I saw what looked like TOS Star Trek, but really wasn't. It may have been during the lean years, before TNG showed up. The audio was directly from the episode "The Doomsday Machine", but the footage looked like it had been done on Super 8mm or 16mm color filmstock, with amateur actors in passable uniforms and rather simple sets. They pantomimed every single scene to the soundtrack. The whole thing was like a serious reconstruction of the episode, not played for laughs. I don't remember if they used original effects clips or made their own. I only saw it once, though I checked through the week to see if it would show up again. It was a very surreal experience. Does anyone else remember seeing something like this? It could have aired in Chicago, Phoenix, San Francisco, or St. Louis given the approximate dates. I think the same group later did a non Trek film called Captain Future.
If you find it, I'd like to know. The closest thing I have to what you are describing dates later, to around 2001, and it's here: http://startrekreviewed.blogspot.com/2009/06/49.html. The Doomsday Machine is the Trek episode which has inspired the most fan films. I have the ones I know about listed under "Doomsday Machine" here: http://startrekreviewed-tvandmovies.blogspot.com/2012/01/2.html
I tell you what: I distinctly remember as a kid on the Channel4 show 'The Big Breakfast' they had a guy on who made a film called 'Dog Trek: The Next Generation'. It was literally a TNG film where he used his dogs on miniature Enterprise bridge sets, in uniform and everything, and I remember him holding up the video case and the bridge was in the garden.
I do not believe I have Dog Trek. I wonder if it's on You Tube... http://www.youtube.com/watch?v=ewRuHi7tJjc
Sadly, I am also missing Cat Trek. I do have "Cats in Space" http://www.youtube.com/watch?v=9DnQLI1XDzI and Star Trek Cats http://www.youtube.com/watch?v=sIVFm0De3OY (3:44)
ST author Andy Mangels was working on the bonus material for the official "Secret Lives of Waldo Kitty" DVD boxed set, but it seemed to vanish before release.
Here's one that popped up: In 1982, little know pop artist L.B. Rayne created an opening sequence for "Star Trek II: The Wrath of Khan". Unfortunately, the producers felt it did not fit the vision of the franchise and they shelved it. Uncovered 30 years later, the music video has been digitally restored and unleashed on YouTube. Now you can see what no man has seen before! http://www.youtube.com/watch?v=M5dHGu4WzCQ