Somebody has done one, because I made 8 (IIRC) windowless CPR 2200 coach bodies for that somebody. I cast up a bunch of regular 2200 coaches and filled the windows with additional resin and sanded them smooth. It was more work than I bargained for, but if you're interested I would do some more for a railwire member. I don't recall who made the decals, but if it was Black Kat and you can get Al to make another batch you should be in good hands; he makes great decals.
I suggest you try contacting Central Hobbies directly; I recall that the Confederation Train project was sort of a Central Hobbies project (or on behalf of one of their customers) and they may be able to help with some of the details.
Geoff (Gooderham)