Are you trying to replace with original, replace with new wood, same pattern, or simply find a nice stock for it?
Dig around if you can get the search to work for you, and check out the terms "Stock Duplicator" IIRC there was a thread relating to the guys that have them around the country.
If you are willing to go outside Canada, start with Treebone Carving. They may have an appropriate pattern. You might ask on the ASSRA forum, as well as on the single shot rifles forum and doublegunjournal.com. Someone may have a take-off that they have been holding onto.
CPA Rifles has several Ballard patterns as well, with pictures on their site.
Just a nickel bet, but I'd bet that there are not enough of them around to make the odds of any of the stock carvers having a pattern of the original military wood in their stores, pretty slim.
Cheers
Trev