I happened across this seller on Ebay, offering HO scale 3D printed 42' and 46' Rio Grande GS gondolas. Here's a link:
If the link doesn't work, the seller is Bonsall Scale Car Shops. I haven't purchased any of these kits, so I can't comment on the quality, but I know models of these prototypes have been long desired by many folks on this list, and I have not seen them discussed on this list.
They look nice in the pictures, and they are certainly more economical than the W&R model! I wonder if the seller is a member of this list?