Creation, is it too late to say that I thought again about your stainless beauty and have a different opinion about why the IR burner doesn't work? If not, then read on.
Fresh air draw is important to proper function of IR burners as well as regular underside burners. On convential grill-style IR burners, fresh air is drawn from the backside of the burner box. On jgame's innovative design, the burner is horizontal over the top of the pie, but the nozzle area is still open to allow fresh air from outside the burner area. You want that - a fresh air source supply just before the gas nozzle sprays into the IR burner. That spray draws fresh air along and allows the gas/air mixture to flame in the IR burner.
FWIIW, I've been noodling on the overhead IR design for some time. But after more thought and some experiments in my grill, I have reservations about the effectiveness. My main concern is that the center of the pie will be continuously exposed to the IR heat, but a given section of the rim of the pizza will only be periodically exposed to the head as the rotisserie rotates the section into "view" by the above burner. Initially I figured I would address this concern by slanting the IR burner so it is closer to the rim of the pie and farther away from the center of the pie - but I don't think this will be enough. Maybe jgame has commented on this and I just haven't seen the post yet.