Alternative to swiss cheese
Are you opposed to "fake cheese", AKA "cheese food products"?  The best known at least in the US is Velveeta, but there are alternates including recipes you can find to make your own.  They would have a different flavor profile than Swiss and others that I call white cheeses.  Home made versions are usually a combination of America, Cheddar, and milk or dried milk.  

Con side: It is what many refer to as cheese flavored plastic and cheese purist scoff at even considering it.  The flavor profile tends toward bland, not the more complex flavor of name cheeses.

Pro side: It was specifically developed to melt smoothly, consistently and without lumps and far less tendency to separate into a layer of oil than many real cheeses.  It is largely credited with the rise of popularity of grilled cheese sandwiches in the US years ago due to its ease of melting and that it will stay melted.  It is commonly used in many quick cheese sauces for the same reasons.

If you mess with one of the home made recipes to duplicate it, it will typically take a few hours to prepare it (some use gelatin and are faster), but also gives you the opportunity to customize the flavor profile.  Commonly spices and tomato are added.  You could then experiment with adding your own favorite cheeses to see if you could duplicate the ease of remelting while retaining closer to your taste in flavor.