Hi,
I've wrote a small article/tutorial about how you can change animation speed in Unity3D. I was in the position of doing that and had to do quite a bit of research to use the right method for my particular problem, but I've learned the following in the process:
http://www.jungle-troll.com/2013/11/07/animation-speed-unity3d/
Please let me know your opinions and share your own techniques on the matter.
Cheers,
Mihai