This is a Yi saber with the typical Tibetan style blade and distinctive large round pommel. I do not know if the Yi produced such blades or traded for them from Tibet, but they are identical to Tibetan blades. The handle, pommel and scabbard are fairly diagnostic though scabbards from Eastern Tibet are very similar when done without fittings. The pommel is the real sign this is Yi. This one may be ivory, but they come in a variety of materials while all maintaining the same shape. I have posted several pictures, as most people are not familiar with this kind of sword.
http://i77.photobucket.com/albums/j6...duation376.jpg
http://i77.photobucket.com/albums/j6...duation375.jpg
http://i77.photobucket.com/albums/j6...duation372.jpg
http://i77.photobucket.com/albums/j6...duation374.jpg
I hope these are interesting.
Josh