The International Arboretum is in Rochester New York and has a great selection of Bonsai and supplies( (including many fine Shohin) as well Masterpiece Bonsai on display, including many outstanding Shohin Bonsai! You may also get a chance to meet Bill Valavanis. Bill travels all over the world teaching Classical Bonsai, he just returned from the land down under this week. He is a great teacher and loves to talk about Shohin Bonsai.
You did not mention when you are coming, but from September 10-13 SHOHIN BONSAI 2, the 2009 Bonsai Symposium will be held in Rochester. The last one was 2 years ago and was excellent. One of the features is the largest Shohin Bonsai Exhibit in North America. Details on the Symposium can be found at internationalbonsi.com
The 1st U.S. National Bonsai Exhibition Exhibition Album was just released and has many amazing Shohin Bonsai. I just picked up my copy and it is superb! I just did a quick count and there are about 30 pages of 192, that feature multiple Shohin Bonsai. It is a great way to study both excellent trees and the displays. If you get one, bring it with you and ask Bill to sign it.
Let me know if you have any questions, I would be happy to help you!
Mark