I've been beating my head with the same problem and I don't have a solution yet for affordable wood.
I'm off the hook for a while because a relative scored some Apple from Wenatchee Wa and is driving it down. I just provide room, board and a Q. Still, that's a temporary solution.
I've tried the hardwood shops but it's all furniture grade and I just can't bear to pay the price although it's less expensive than bags at Home Depot or the hardware store. I even have a friend who is a wholesale hardware dealer int he Eastern US who would give me the Oak if I pay for the shipping. Still not cheap enough for me.
There are orchards near me and there certainly are in Eastern BC and that's where you and I may have find our wood, -- in the orchards. I'm told the orchards prune in late winter and the size of wood we want for a WSM is laying on the ground. I've done a couple of smokes with a plum tree pruning which was just fine. Tastes fine and hasn't killed me yet.
Who would have thought the most important accessory for a smoker is a chain saw? /infopop/emoticons/icon_rolleyes.gif