Edit: awwwwww nuts, how did I miss the other threads for this? >_<
Hey all, I'm not sure if someone's already done this (I couldn't see a thread) but:
After tinkering around with the WotLK alpha client, I managed to find the Frostmourne model and texture and switched it with the Corrupted Ashbringer.
Image:
In Game with Savagery:
Download Link: frostmourne.mpq
It all works perfectly in game, particles and such.
Enjoy!
-Votty