I kitbashed/scratched an SD40-2F about 19 years ago, see photos. A friend did PR for CP, and their HQ wanted to see what the loco would look like and needed a model, so I got to make it. I used friend Patrick Lawson's article in RMC to make mine.
Used the cab from one Athearn loco, the back end from another, and styrene inbetween. Kind of coarse compared to the Kaslo model, but I didn't have a whole lot to work with. The sides and roof are styrene, with the doors and panels from another model, with some scribed on. I scratched the rear radiator grill areas. The model is not powered, as they wante it mounted in a display case with a clear acrylic cover.
These photos are scans of contrasty color prints, and since I did not weather the chassis or trucks, these areas are all too black.
CP may have wanted 10 or more copies, but I lost interest after spending about 52 hours making this one. It was a neat and rewarding project!