The 191 at the Narrow Gauge Convention was fabricated using a LOT of extruded foam. I tapped it with my figernails to see what it was made of.
I agree with you about the structure kits at the NG convention: if Atlas and Lionel weren't hawking their buildings in Denver, several of the smaller manufacturers were. While many of their products are aimed at more skilled modelers, they do a much better job at depicting structures from earlier eras than many of the latest offerings from Lionel and Menard's. I'm not knocking Atlas, Lionel or Menard's (They're in business to make money), but not all of us have our layouts set from 1955 to the present day. And if narrow-gaugers can use O scale structures aimed at three-railers and other broad-gaugers, I don't see why three-railers can't use structures built for the narrow-gauge market.