Slice mushrooms. Cube pepper. Dice onion. Set all ingredients aside.
To assemble: After dough has risen, punch it down. and knead 1 minute. Cut off 1/3 of dough for the top crust and return it to bowl and cover. Roll out remaining dough to extend 1 to 2 inches over a 14-inch, 2-inch deep, spring pan. Lightly grease the sides of the pan, but not the bottom. Line the top of the pan with foil so that it extends out of the pan which helps prevent the crust from browning too much.
Fill the pizza shell with layers of sausage, pepperoni, onions, green peppers, mushrooms, and olives (pizza can be stuffed with anything, but meats should go at the bottom of the stuffing). Top with mozzarella, parmesan, and Romano cheeses. Roll out remaining dough. Crimp bottom and top crust together trimming off excess dough. Make several slits in the top crust to allow steam to escape while the pizza bakes. Cover edges with foil to prevent excessive browning. Place pizza and sauce (in a separate uncovered casserole dish) in the oven. Cook for 40 minutes at 475° oven. Allow pizza to tool 5 minutes.
Ladle sauce over cooked pizza and serve.