There are cold hardy cherry shrubs:

http://www.honeyberryusa.com/

There are a number of species of bush cherries but they are all tart or sour cherries rather than sweet cherries. Still tasty and not as tart as most sour cherries but not the same as a sweet cherry.

Bush cherries

Yes. This is probably 'Carmine Jewel', or an even better recent release is 'Juliet'.

These are basically in the "sour" cherry group but they are sweet.

This specific cherry group is very hardy, can grow where normal cherries do not grow so well.

Thank you for the replies! I really don't care if the cherries are sour or sweet -- what I liked is that the bush was small, very prolific, and had full-size cherries (easier to pit). I grow Evans cherry and the fruit is small! I wonder though, if that bush produced an edible cherry then why didn't any people, birds, or squirrels eat the fruit?! Are some cherries non-edible?! The cherries on this bush were definitely large and dark -- they looked just like what's commercially available here as dark sweet cherries.

Were these fruit definitely cherries? Did you ever open one and find a pit rather than seeds? Could they have been crab apples?

Definitely cherries, floral. They had the right stem, shape, size, color, and pit. I just didn't taste one because the wildlife wasn't eating them!