This is another not-technically-Flower-Mound pizza place, but one that's worth trying.  Their 20" pie feeds 4 easily, usually with leftovers, and they have some neat specialty pizzas worth trying, and some nice premium toppings.  My favorites are kalamata olives and feta cheese. 
I can't vouch for their pastas and sandwiches, but as far as I'm concerned, this is the other contender for top pizza place in the area. 
If you work in the area, they also do a by-the-slice lunch deal that's pretty reasonable.

http://www.carmineslewisville.com/new-york-style/
972-956-0705