I will often make Denver sandwiches in the evening for a quick, yet healthy meal. When making them at home, you can be as creative as you want to me. You can add as many extras you want to the omelet, and use whatever kind of bread you have on hand.
My favorite Denver sandwich recipe is just a simple ham and swiss cheese with some onions and mushrooms served on rye bread. I will also add some bacon if I want to go to the trouble, otherwise I leave it out. I know there are traditional ways to have this sandwich, but you really can't go wrong using your favorite ingredients.