That Campbell Station Wagon conversion is beautiful, rare, and valuable.
They were not really Suburban conversions because they started with the 3x12 (Chassis w/Windshield Cowl (no cab)) - 1/2, 3/4, 1 and 2 ton models (8 to 18 passengers). This can be seen in the documentation - it's nice and uncommon to see the documentation.
Wow.
Tim