Funny, once I made up my mind to get an M-305, and decided I wanted one of the shorter barrels, and all the retailers had were the longer ones. So I still haven't gotten around to it. Last time I looked Marstar had them with the long barrel. But you might have to buy an SKS with it in a package deal.
And yes, you can't have a genuine M-14, they were selective fire and converting them from full-auto to semi-auto isn't good enough, so they can't come to Canada. There may be some already here with owners grandfathered for prohib, but if you aren't already qualified for a prohib license you can't become so.
The long and uncertain way around that is, I think you can buy or start a gun business that can be licensed, and then your business can buy one, if you can find one for sale.