You must mean Creatures\SMSpineBreaker\Skeleton.nif
i was actually looking for the actual mesh object for the super mutant, not the skeleton. anyway, i've found it (or one, at least) under SMcaptain.nif. thanks though.
i've got close to zero experience animating organic models[*], but it is something iv'e been interested in doing for a long while now. i think the sitting animation is not
too complex, so i'm going to try and make at least a rough animation of the SM sitting on the ground. if i'm successful maybe someone else (**cough**
saidenstorm**cough)
can come in and clean it up and make it look more natural.
[*] i've actually gone through the blender noob-to-pro section on animating the walkcycle, but i could never make it look right.
E:
i can't believe i didn't see it earlier, but the mesh i was
really looking for is "m01_smspinebreaker.nif"