I used a BSA unpacker and have copies of all of the vanilla morrowind resources listed under an _ext folder in Morrowind's main directory. I opened a model from these assets (the Cliff Racer xnif) in Blender and made some minor adjustments, trying to make a helmet. I deleted the entire mesh, save for the head, rotated it into a proper position and did some vertex editing. I also deleted its shadow and bone elements. The .nif is saved in a custom directory in Morrowind's Meshes folder, and its texture (a copy of the cliff racer's head DDS) is located in a directory under Textures.

Now, when I loaded the .nif as a body part model, it didn't seem to have any trouble. i applied it as a hair armor piece, saved it, and put that piece onto a helmet. But when I put that helmet onto any NPC, they will wear it, but there's no sign of my saved model; their hair just disappears. When I try to place any object in the world using that model (static, armor world art, activators, etc.) the CS crashes on the spot. Does anyone know what might be causing this problem?

EDIT: Simply loading a duplicate of the Cliff Racer's xnif file also causes the crash... Is there any way to simply extract the model, without having to use outside editors like Nifskope?