Brown and drain sausage; sautee mushrooms. Mix with green onions, pimento, salt, pepper and dry mustard. In a bowl, mix eggs, milk and Worchestershire sauce. Spray oil a 9x13" pan. Cover bottom with a layer of bread slices. Spoon sausage mix over. Top with remaining bread. Pour egg and milk mix over. (Can be assembled to this point and refrigerated overnight.)
Bake at 350 for 70 minutes. Sprinkle with grated cheese and put back in the oven til cheese is melted.