Some places in the states sell the G36 folding stocks for the SL8, but I have not seen any shop in Canada with them yet. In the states they are about $265 for the folding stock, but they likely won't ship to Canada. A company called "Top Notch Parts" used to sell the SL8 G36 stock and were rumored to have an adapter kit in the works, but they vanished.
It takes a fair bit of work to get the HK G36 stock to work. There is a lot of info on this in the hkpro forums.
Personally I agree with Wildbore and would go with the HERA stock adapter. Way easier to install and it looks even ###ier then real G36 (personal opinion of course.)