I just have started with a basic body assembly for building PRR's motor car #4663, a shop-rebuilt Pullman-Westinghouse. It was streamlined (shovel-nosed) and rebuilt to diesel-electric by PRR's shops.
I use a Aristo doodlebug body; body and roof lengths are extended with Aristo HW left-over parts from the McKeen-projects.
Front truck will be from a USA Trains NW-2 (similar to the M-23), the rear truck a shortened Aristo HW-truck.
The shovel-nose will be made with styrene sub-construction and styrene lay-over panel (similar to the McKeen noses).
Pictures will follow as soon as some progress is worth to show.