Here is what I've been using to cook my pizzas for the past year or so. The grill has 3 heavy cast iron burners along the bottom and an IR burner along the back. I run them all together (the grill does say not to do this...) and also build a small wood fire in the back corner. With this set up and the insulation, I can get the air temperature over 900F (in the summer), though I generally bake my pies at 750-775. The wood fire adds some heat, but I mainly started doing it for the flavor - that's the theory anyway. I can't say for sure if it adds all that much. My typical cook time is about 2:00 - 2:15.
To get the heat up inside the grill, I use two insulating blankets. The red blanket on the bottom is a double layer of ADL Insulflex 32oz Pyroblanket. It's designed for very high temperature industrial applications (such as protection from welding splatters) and can stop open flames without a problem. It doesn't have a whole lot of insulation qualities, but it brings the temperature down enough that I can a lay a Kovenex Rapid Response EMS Blanket, folded into four layers, on top. The Kovenex blanket is pretty good insulation and keeps the heat fairly constant. Neither of these blankets burns or gives off any fumes or smell when heated, however I found out the hard way that the Rapid Response blanket will darken over time and eventually disintegrate if placed directly on the hot grill.
The stone is a FibraMent-D grill stone. It is thick and holds a lot of heat, and it comes with a metal pan that not only protects the stone from the flames but also reflects some of the heat down and away from the stone which allows me to keep the burner directly below the stone on high without the stone getting too hot.
Here is where I got the blankets:
http://www.adlinsulflex.com/fire-blankets/pyroblanket-32-ozhttp://www.thefirestore.com/store/product.cfm/pid_3033_kovenex_rapid_response_blanket_professioanl_ems_10oz_58_x73_/
