I feel your pain with peonies but try festiva maxima if you can find it. It blooms for me but is a slow grower. all the others always get burnt to a crisp. I'm not sure if you ever thought about growing citrus but Stanley McKenzie has a nice selection of citrus that will work in your area.
http://mckenzie-farms.com/phot... other edibles you may want to try out are pomegranates, figs, persimmons, loquats, guava, mulberries, and goumis. If I ever hear of a heat tolerant currant I'll be sure to let you know as I'll be adding it to my garden also.