Hey there West,
A couple years ago I attended an info session about growing hazelnuts commercially in eastern ontario. Turns out it was actually an info session about how we
can't grow hazelnuts commercially...at least not for big companies. They said there was development happening to breed for a hardier tree that would still produce a large quality nut, but that the trials they had done weren't successful yet on a large scale.
Sorry I can't remember more info about it.
You've probably already read this, but just in case:
Hazelnuts in Ontario
I don't have experience growing any, but if you haven't come across these varieties you could check them out:
Gene
Carmela
Grimo