Yush, just this thing uses the NiAlphaProperty, which I've seen behave all weird without vertex colors present for those fur-patches on various creatures. That and look up the ShadowMere's nif file, for instance, and check out the vertexes around the eyes - they'll have a reddish tint and some vertexes are fully red. On the regular horses, vertex colors are set to white, but also enabled in the game's original files.