Tom, you have already helped a lot already, and I have bought one of your coaches. After I made the comment about shops I found the page on the Shapeways website, which was not as easy as it should be, almost like they are hiding it.
I would not expect to make a fortune but it would be nice if someone got one of my models. I have stressed that its not dead scale(many military models seem to mix up scales as well), but captures the spirit of the loco.
Just an idea from your collection, the coach seating in 1/35 would be popular. Would make nice garden and station benches.
About 20% would be nearer the minimum I would probably add on, but you have to look at what is average price for models in chosen scale. From what I have seen railway modellers in 1/32 and 1/35 are prepared to pay more, but military modellers in same scale have relatively low prices, unless its resin or metal. Price of figures might reflect cost of production and design, but if you need a lot for a scene, the cost is prohibitive. Someone else made similar comment concerning Scalelink figures, nice but prohibitively expensive, but actually cheaper than some others. One reason I am searching out plastic kit figures which can easily be adapted.
Narrow gauge Francophile interested in 1m, 60cm,50cm , 40cm and smaller gauges . Build in scales from 1/6th to 1/24th. Also 1/32nd and 1/35th using 16.5mm track to represent 50cm and 60cm gauges. http://www.rue-d-etropal.com