Hey all. I don't mean anything by this but to defend my very crude design.
Gary's link is a nice looking mod, but still doesn't get to the problem of a pizza on a grill. The challenge is uniform cooking - top and bottom at the same time. Every time that lid comes off, the volume above the surface of the pizza that was put on there goes down alot. A hot surface, no matter how it's created is a hot surface, not an oven. I wish this worked, but when you toss it on, the bottom will cook faster.
With my primitive door cut into the dome (an extra dome found in the trash), the headspace doesn't cool down much at all when the pizza is slid on to the surface. I did some measurements using a datalogger/thermocouple that show how much the headspace cools when the lid is removed versus the little hatch opened
here, it's pretty significant.
I've been having a blast and getting some mean pies from this thing.
ps, I'll wager the Grill Dome (I just read about them) is superior given the behemoth thermal mass. I still don't know how long the dome opens before the pizza is put on. This is still important.