“we might not want to just look in one department, this is a movie that noone has seen in year (most likely) sinces 1978.”
That’s exactly what the SAIC’s Video Data Bank  is for:
“The Video Data Bank is an essential destination for video art, media art, video art history, art resources, artist interviews, curated programs, and much more…”
But they couldn’t help me. A 34 year old video shouldn’t mean anything to them, one of the currently most viewed videos is from 1970  — over 40 years old!
“Anyone, anywhere inside that school might have clues to the whereabouts of the movie, it's not like it is a easy thing to lose :/”
You would be surprised :) Never heard about the Houdini voice recordings? They were completely lost until someone found them in an attic after the owner had died in 1970, 56 years after the recording was made . It is still the only known recording of his voice. (Listen @ Internet Archive: .)
Nobody had any clues about the whereabouts. To be honest, most people never knew of its existence. The only reason we have it is because somebody stumbled upon it. This could easily happen with this film too, no matter how much you ask around.
Keep us posted if you get any answers and thanks for your input! :D