I think planting trees is a worthwhile endeavor for any reason, but keep in mind that though all will provide decent shade, they may not all offer the ease of pollination, cultivation, harvest that you may want to deal with. Some self-pollinate, some cross. Others take many seasons to produce viable fruit, and others have their fruit eaten by animals before you can get your hands on them.
The harsh sunlight shouldn't be much trouble with mature trees, but you should be wary of winter. Once established the rocky soil will become less of an issue as trees are generally hardy once they've taken root.
I would look at the following fruit and nut trees.
- Black (or any) cherry (possible, but I wouldn't recommend)
- Orange (Osage is a common variety)
- Mulberry (messy)
- Plum (especially adapted for full sun)
- Apple (Enterprise and Liberty are common cultivar recommendations)
- Apricots and Peaches (most varieties should be fine)
Plant a variety to keep pests to a minimum. I'd recommend buying mature trees, otherwise you'll be waiting years for a harvest of any sort and will certainly be without shade.