Hmm thats an interesting idea...i tried to edit .glm files for other reasons but they always ended up corrupted and my PC froze when loading them. I'm no programmer so i have no idea which software could do this without "damaging" the files...
i know that Jolt managed to do this in his JO Darkness mod with Jan and the stormtroopers from ja and included the _humanoid and animation file from the ja only in a different directory ".../_jka3noid/_humanoid.gla" and the glms all point to that, thus the models work in jo