This is a tough one, because it seems the primary differentiator from other frozen, or non-frozen, pizza is that it is “Saint Louis Style”, and all that that implies based on the story you will tell about it. Therefore the name will probably have to have something to do with “St. Louis Style”, because an “Antonio’s Pizza” product in a supermarket freezer could be any kind of pizza.
You can use this to your advantage: since “St. Louis” isn’t the first thing to pop into anyone’s mind when they think “Pizza!”, using some form of “St. Louis (style) Pizza” immediately differentiates your product from all the Tony’s, Antonio’s, Domino’s, etc. pizzas already out there.
Pizza STL
STL Pizzaworks
Arch Pizza
Saint Louis Pizzaworks
St. Louis Pizza Company
Gateway Pizza
Gateway City Pizza Company
Saint Louis Armstrong
STL Gateway Pizza
Pizza Saint Louis (“…get a ‘piece of St. Louis’ with Pizza Saint Louis…”