I received my first pair of 3d printed Trail King bottom dump trailers via UPS today. I was very impressed with the print quality, and the model turned out as intended. Of course, this was a fairly conservative model, without a lot of detail or complex parts. It scales out nicely compared to my grain trailer, and a typical tandem axle tractor under the king pin. I dropped them both into a jar of Bestine tonight, and will hopefully get around to painting them soon. These will get a coat of white paint, DOT striping, and aluminum fenders. Not a huge challenge compared to the grain trailer.
These are now available through my Shapeways store: http://www.shapeways.com/shops/NScaleAddict