Cold Hardy Nut Trees

[shin]

Can anyone recommend any cold hardy nut trees?

I'll be growing my trees in PA which is zone 6.

I've been looking at the different cold hardy almonds out there. Some folks've raised 'Hall's Hardy' but complained they're more for show than for the nut. I also don't want a variety that has cyanide as a concern..

[Skandi]

Hazelnuts and walnuts both grow here in denmark (and fruit well) Walnuts are a bit of a long term solution but hazelnuts are fast growing.