How can I create a sweet pizza that looks like pizza?
If you make the base neutral - a typical Neopolitan dough would do - you could use white chocolate shavings to give an appearance of cheese as well.  I would keep the amount light.  

While looking to verify this idea, I found a recipe that gave me a few more pieces of inspiration.  Instead of carmelized sugar banana slices, try dried fruits (strawberries, sweetened cranberries, raspberries, etc.) for your toppings.  These will look like sausage bits or pepperoni.  You can also use pineapple and make it look like a Hawaiian pizza.  

You could also use almond cream as a white sauce or as some of your cheese for a richness that is not too sweet.