Bethany,
Try The Newark Museum in New Jersey. I don't know specifically about Nepalese
Sherpas, but they have a spectacular collection of Tibetan art and artifacts.
The Asian Art Museum in San Francisco is another possibility, as is the Nepal
Studies Association, Department of Geography, Portland State University, OR
(phone 503/725-8044 or 8312; 1-800/547-8887 and ask for 725-8312).
Mac West
Informal Science