Thanks to Roundhouse, the cars of the GD Line (John Allen's Gory and Defeated [or as I think he sometimes meant the gosh darn line]) live on. I did not know this until the model train show I went to last weekend, where I came across some of the cars. They are beautifully done. In HO.
The cars can be found on Ebay quite often. Rarer is the 0-6-0 that Roundhouse put out to pull the cars. I've never seen one listed for sale.