Preheat oven to 325°F.   Heat a sauté pan over medium-high heat. Add the sausage and cook until golden brown and the fat is rendered, about 5 minutes. Add the onions and bell peppers, and sauté until soft, 3 minutes. Add the green onions and stir well. Add the white wine and reduce slightly, stirring, about 1 minute over high heat. Remove from the heat.  

Place the bread in a large mixing bowl. Add the milk and cream and stir well. Let sit for 5 minutes.  

Pour the melted butter into a 10- by 13-inch casserole dish, and coat the sides and bottom evenly. Pour any extra butter into the bread mixture.   Add the sausage mixture to the bread mixture. Add the eggs, grated cheeses, salt, black pepper and cayenne, and quickly fold mixture together. Cover with aluminum foil and bake for 1 hour. Uncover and bake for 15 minutes. Remove the casserole from the oven and increase the temperature to 375ºF. Spread the sour cream evenly over the top and cover with grated Parmesan. Bake uncovered for 10 to 15 minutes, or until the casserole is lightly browned on top.   Serve hot.