The Scott boiler was invented by Mr David Scott round about 1906 and was featured in M.E. mag
It had a 2.5" top drum with multi tubes coming down into the fire box for firing with Roaring Petrol burners.
It was further developed by Mr A.A. Rayman and is still used by the straight running Brigade, Phil Abbot et al. ( pic enclosed. )
I have made one and it's a very fast steamer and capable of high pressures mine worked at 150 psi.
As far as is known none have been made full size it's purely a model application.
George.