In my research, I did see one company who makes custom dog jackets and wetsuits. That might be the way to go for a larger dog.
The coach did give me the dog's coat as another reference for sizing. It is a very simple design. Basically a long piece cut with a contour, a collar and an added strap. I have some amazing Malden Mills fleece leftover from a bag order. It is a thick two sided fleece. I made up another little coat too.
|Dog Fleece Coat|