Head to Canada
If your season is over as is mine you might want to check out the Canadian Peony Society at this site. http://www.peony.ca/ Their annual meeting and show are the first few days of July. I have not gone "yet" but from the pictures and comments I have heard it is a great show. The garden it is being held at this year has been on several shows for art and gardens.
The American Peony Society had 36 tables along with 3 display tables with some brought just for display and not competion. Many older varities. Depending on the season Canada should have even more of the older varieties which you can not find in the states.
I was in the area of the APS show last Sunday and stopped to get my last fix for the season. Wonderful blooms.
The APS meeting is coming to my area next year maybe I will be able to spend more time. Will post pictures of the flowers when I can.