Layered Deli Loaf

In a small bowl, combine the mayonnaise, horseradish and mustard. Cut bread in half. Carefully hollow out bottom and top of loaf, leaving a ¾ inch shell (discard removed bread). Spread butter on cut sides of bread. In the shell, layer ham, a third of the mayonnaise mixture, monterey jack cheese, turkey, a third of the mayo mixture, cheddar cheese, roast beef, remaining mayo mixture, tomato, pickle, onion and lettuce. Replace top. Wrap tightly in plastic wrap and refrigerate for at least one hour. Cut into quarters.