Carpathian/English walnuts

I'm seeking reports from people experienced with Carpathian/English walnuts (Juglans regia), especially in colder areas. I'm in Zone 5. There seem to be many reports of varieties said to be hardy to zone 5. Is this legitimate?

I'm also curious about the time to fruition. I've seen really widely varying reports. Some say you could see nut production in a few years if you purchase a bare root tree that's presumably a few years old. Others say to allow a couple decades for much production. Can anyone provide input on your experiences with time to fruition?

I'm hopefully going to have a few acres to my name in a month or so and this is a tree I'm really interested in planting.

They offer Carpathian walnuts in the spring tree sales for the conservation districts in the UP of Michigan.  Therefore I'd think they must have good enough luck with them in zone 4.