Spread mustard evenly over both slices of bread. Place 2 slices of the Swiss cheese on 1 slice of bread and make this slice the bottom. Place desired amount of sauerkraut on top of the cheese. Add liberal amount of horseradish, then Thousand Island dressing in this order. Add several banana pepper rings. Drape in hefty portion of corned beef and repeat process for a second layer. Finish the last layer with 1 more slice of Swiss cheese and the other slice of bread.