Pro hobby: I'm pretty sure someone (probably K-Line) made a six-car Evans already.
Here is some information found elsewhere on the OGR forum: K-Line model shown.
The 6 car Evans Auto Loader was built by Evans for the New York Central. The superstructure was mounted on a standard 53 foot NYC flat car. This unique prototype carried two more autos than could typically be loaded in a boxcar and one or two more than could be handled by the highway carriers of the day. While the 6 car Evans Auto Loader represented progress toward the future and inspired a popular post war toy train car it never reached the full production stage. K-Line produced a full sized replica of the Evans Auto Loader as their K694.