Sean, there is some great sources for stock blanks up here - at least in Ontario.
No, they are not cut in the rough shape of rifle already - they come as boards, but they certainly are available.
This piece of curly Red Maple came from A&M Woods in Cambridge Ontario. It was a piece of 8/4, 61" long and just shy of 10" wide. I got two stocks out of it and the price on it was 65 bucks. They also have curly Sugar Maple and numerous grades of Walnut (8/4 and 12/4 is readily available)
This is the first "blank" I got from the board
and the second -
There is also KJP in Ottawa that carries Maple, Walnut, Cherry, Flame Birch etc or Monaghan Lumber in Peterborough.
I have used wood for stocks from all three of those sources and if I dig I have a couple more suppliers as well.
The main drawback of simply buying a board is you need to pick through the pile to find the right grain orientation etc (which is why the cost is less then buying one that has been pre-selected/pre-cut) but there certainly is no shortage of suitable wood if you do a little leg work - although there is a couple of suppliers up here that will mail order as well - just need to tell them what you are after and they will pick something suitable - Exotic Woods is one such company
http://www.exotic-woods.com/index.html although their price per board foot is a bit more than the suppliers I deal with.
You can order from the US, but when you are looking at shipping costs approaching 100 bucks for a blank and converting the buck and then maybe having taxes tacked on by CBSA, pursuing local options is worth checking out first.