Don,
I have this problem. It's called trains. I find a locomotive I really like, and it has nothing to do with my main modeling interests, so I go find a train for it. Conversely, I really like scale passenger cars, especially Golden Gate Depot 20" heavyweights. I end up with a bunch in an odd road name and then need to go find a locomotive for it. 
This was a case of finding the cars first. I have a nice collection of 10 CP maroon cars and an original 1953 booklet published by the Canadian Pacific to publicize traveling over the Canadian Rockies by rail. This was a few years before the Canadian, so it is full of great scenic photos with maroon heavyweights pulled by steam locomotives and tall mountains. While the CP division that runs through the Canadian Rockies was the home of the big 2-10-4 Selkirk locomotives at that time, the various H class Hudsons headed up the passenger trains from Vancouver to Revelstoke on the western side of the Rockies and from Calgary eastward.
I liked the BC one so much, I found a sister for it. 2558 is how these appeared in service prior to dieselization. Note the gray boiler in lieu of the silver one. There is one error in that 2858 was actually and H1d which had a coal bunker and did not burn oil. When diesels took over on the long-distance trains, the remaining Hudsons finished their days on commuter trains and in freight service and lost their elegant paint schemes. Some ran as late as 1960.
What I really love about Canadian steam is it has such a nice balance of European elegance and American ruggedness.
I'd really love to find a Weaver 2816 "Empress" which was the H1b class Hudson that recently toured Canada, the US, and Mexico, but those are rare, rare, rare!
