Prepare the crust. In a medium bowl, stir together flour and salt until well combined. Add 1/3 cup butter and the shortening, then cut in with a pastry blender until flour appears crumbly and no crumbs are larger than pea size. Gradually add water, one tablespoon at a time, tossing thoroughly with fork after each addition until dough sticks together. Dough should be only slightly moist and should still retain a crumbly appearance until pressed together between fingers. Place mixture into an ungreased 9 x 13 inch glass baking dish and flatten to bottom, pressing dough halfway up the sides of the baking dish. Melt the remaining tablespoon of butter and brush over crust using a pastry brush. Immediately sprinkle with cinnamon and sugar and set aside.
Make the filling. Peel and slice two of the peaches and place into a medium bowl. Add strawberries, blackberries, raspberries, and rhubarb. In a small bowl, combine 1 tablespoon flour and 2 tablespoons sugar, then pour over fruit and toss until fruit is evenly coated. Set aside.
Preheat oven to 350 degrees. In a medium sauce pan, add remaining peaches (peeled and sliced), cinnamon, butter, corn syrup, honey, lemon jice, orange juice, and sugar. Begin cooking over medium heat, stirring constantly until juices form. Mix corn starch with 1 teaspoon of water and gradually pour into mixture while stirring constantly. Allow mixture to come to a boil. Continue to boil, stirring occasionally, until mixture thickens. Once thickened, stir constantly until the liquid portion of the filling sticks to the spoon when removed from the pan. It should almost have the appearance of cooled pie filling. Remove from heat and add remaining fruit, stirring juices into flour mixture before adding to the filling. Lightly stir to combine and set aside.
Place empty pie crust in the oven on the middle rack and bake until the butter is melted and the cinnamon and sugar appear to have absorbed into the crust.
In the meantime, prepare the streusel. In a medium bowl, combine all ingredients and stir together until crumbly and all dry ingredients appear a bit moist. Set aside.
Remove crust from the oven and top evenly with pie filling. Cover with the streusel, paying special attention to the sides as the filling tends to bubble up over the topping along the edges. Bake on center rack for approximately 45 minutes, or until crust appears golden and streusel is crunchy. Remove from oven and cool, then slice into 12 pieces.