Try the gluten-free animal cookies, finely crushed and mixed with butter as pie crust.
We tried it once on a lark, trying to learn to cook for a gluten-free relative. It worked so well that we were amazed! The cookie crust stays nice and crispy. You can mix it with butter (and a little sugar if you like it sweeter), press into the pie tin and prebake about 10 min. before filling.