In a large bowl, blend cream cheese, sour cream, 1 cup of jack cheese, mayonnaise, crab, and shrimp.
In the bottom of an approximately 12 inch round serving dish, spread the seafood/cream cheese mixture. Pour cocktail sauce evenly over the mixture. Layer with green bell pepper, green onions and tomato. Sprinkle with remaining cheese.
Bake in a 350 degree oven for 30 minutes until cheese is melted.