Where is your temple?
This is my 2nd trip to Tibet, and I have been to the Tibetan areas in other parts of China. So, I don't think I will buy anything this time. But you may want to buy 臧红花,冬虫草,人参果 and fungus(mushroom) for boiling soup. You may also buy some accessories like bangles, choker as gifts (some are unisex) which are very cheap. If you like clothing, you can get some nice T-shirts and sporty jackets in Lhasa. It depends on where you go actually.
I also think you can consider bringing a PnS, less hassle. Tibet anyhow take also nice;p I brought 2 bodies, 2 lenses the last round, very the heavy..... This round I will bring 1 body,1 lens (18-200mm), 1 Pns and tripod.