Those come from "Jedi Outcast" ("Jedi Academy" would use the same, no doubts to that). And I would bet that LEC used the same clips for previous "Jedi Knight" (extracting them could be tricky). No luck with "Behind the Magic" documentary discs either. I'm afraid that's all I could do. Anyway, good luck on your project.
BTW: there were at least two popular series of games (i.e. "Mechwarrior") - some sort of a simulator - dedicated to huge walking "robots". Too bad that LEC never made an AT-ST / AT-AT simulator (I don't mean arcade shooter like the "Battlegrounds", but a game more like "X-Wing").