I like spanky's suggestions; and cuban tree frogs shouldn't be to much trouble to find at your local shops. These remind me of our native grey tree frog and the cope's tree frog. They look identical, but have different songs. Scientific name: Hyla versicolor for the grey tree frog. I am unsure of the Cope's name.
I'm planning on raising some tadpoles of these and keeping them in a 29gal setup I'm working on. I find them rather interesting, and like the idea of owning natves - feels more like my outdoor home.
Whatever your choice, I wish you well!