Well, as far as I know the old SIR was just bought out by Cabelas...that should have some big foots. They are run out of Manitoba...Winnipeg maybe? Check their website...although their website isn't very user friendly, it make take you time to find them....unless they have changed it.
You could also order them online from www.canadianwaterfowlersproshop.com
. They aren't out of Manitoba, Alberta I believe. They have a wide selection of dekes...but with the dollar the way it is, you might be better off ordering them via Cabelas out of the states.
Again, not out of Manitoba, but try ebay. We bought 5 dozen off some guy on ebay last year. I find that is the cheapest place to find them.
Hope this helps...