This fowler clone boxcar is a DRGW prototype that was done a Shapeways (by mmyers05) and would be a great starting point. Sand the ends and door smooth, add details and a new RC or simiilar X29 door.
This models is from mmyers05 on Shapeways:
This is an excellent example of the level of detail that can be achieved for wood and textured models with the current printing technology. I plan to modify mine as a CNR 40" fowler prototypes with 4/4 ends as the CN 40' cars had steel ends. I have about a 10-year old scratchbuild in progress as well that I need to build up and cast.
There were hundreds of the 40' variety and tens of thousands (literally) of 36' versions of Fowler/Dominion patent type boxcars built for CNR, CPR, and TH&B. Many US roads also had them. Refer to the Mainline Modeller 5-part series by searching for Dominion or Fowler box cars for drawings, photos, rosters, etc..
Best regards,
Michael Livingston