I am planning to make a pizza oven fueled by a pellet rocket stove. I've seen great things online about plans for rocket stoves and modifying it for more air, more temp, etc. What I can't find is a formula or rule of thumb for getting X temperature at the output from X amount of either pellets or air.
I want to make my rocket stove terminate in the back of a dome which will be the pizza oven, then the front opening will have a flute for exhaust. I don't know if this is a worthy attempt because of these unknowns. I want 900F oven temperature. I had concerns over regulating temps and if it'll even get that hot.
The thing with rocket stoves is most of the heat goes up the chimney, so while I have seen pellet BBQ rocket stove designs that worked until the tubes burned out, getting the heat transfer that you want for pizza might be a tall order. Pellets are normally for steady state cooking. I guess there is a demand for that given the extremely expensive gas models there are out there, but the traditional pizza oven seems a lot simpler if you just want to make the odd pie.
I think a major factor in the best answer for you is how you want to use it. Do you want to have an occasional afternoon/evening cooking session, or will you use it regularly for a whole day? Do you have a particular need to use pellets (presumably automatically fed), or could you use wood?
I have an L-tube rocket-fired cob oven, about 27" diameter x 20" high dome, with a 6"w x 9"h burn tunnel and 6" diameter heat riser. It splits into several channels under the oven floor and enters the dome at the edges, then exits by a 6" chimney above the door. It works well for normal baking, but does not generally get above around 500F. With a more direct flue design it would probably get significantly hotter. A smaller/lower dome optimized for pizza baking would probably increase the heat as well. This design is very economical on wood, using several wrist-sized sticks per hour, and gives steady heat due to the mass.