I work in Cupertino, CA, home of a restaurant called ViVi's FELAFEL PIZZA BURGER.
Every year or so, I ask them to make me a felafel pizza burger, which is quite obviously a hamburger bun with felafel balls, pizza sauce, and mozzarella.
Still can't. But they will make a pizza sandwich (french bread, sauce, cheese) with felafel balls on it. It's delicious.