I ran across this oven in upstate New York.
The sheer size of it is impressive (read 'scary'). The trailer and the multiple layers of steel tubing, recycled oil tanks, levers, chains, etc., weigh many tons.
The complexity of the chambers, baffles, and swing-up chimney make this 'oven' a true Rube Goldberg invention.
The owner told me it cooks everything great.
I can only say, "If welding is what you do, hey, weld away. Bread has been baked in stranger devices, though none come to mind at present."