Instructions: The zip contains 3 dds files. Put these into ..\Morrowind\Data Files\Textures . They won't overwrite anything unless you've installed custom werewolf textures in that directory before (or other textures of mine). To revert back to a regular stock brown werewolf, just delete the three textures.
These are just textures, designed to change the look of your werewolf. The only side-effect is every other instance of the Bloodmoon werewolf will look the same. I played through the entire werewolf portion of the main Bloodmoon quest on Solsthiem and ran in to no problems. Every other werewolf I saw was colored like mine, but no game-stopping technical conflicts.
Anybody can use these textures for gameplay or modding purposes, as I take no credit for them. These are just modified versions of Bethesda's excellent werewolf texture. Enjoy!
-Emberwolf, chris<at>anukki.com (replace <at> with @)
Arctic Bloodmoon werewolf
Download: Arctic Bloodmoon Werewolf
Dark Bloodmoon werewolf
Download: Dark Bloodmoon Werewolf