More than a dozen competitors are racing to become the dominant player in the fast-casual pizza segment. Their concepts are similar, based on the Chipotle system of assembly or down the line ordering, with some slight variations in their individual processes, prices and products. Customers can order and then watch their pizzas built by hand. The custom-made pies are then cooked in just minutes. Here’s a look at how this new gourmet pizza space is taking shape with examples from the 12 leading players.