Blueberries are surface-rooting and need acid soil. You could consider raised beds for blueberries or for several of the other fruits you list. Here's one example of how to build a raised bed. Maypop is invasive and a raised bed or large container could help control it. You might also consider "Incense" passion fruit (might need a little winter protection where you are).

Here is a link that might be useful: building a raised bed

Many things will actually grow OK based on my experience, they will just spread out instead of down. I have a peach tree planted above a huge rock which is doing fine. I didn't know the rock was there when I laid out the row and I already had the tree to plant there so figured what did I have to lose to try. I also have a couple pear trees on rocks. There may be some disadvantage such as getting enough water, drainage, etc however which did not arise for me. Blueberries are very shallow-rooted and I second that recommendation. They are not "unusual" but I would much rather have blueberries than any of the unusual things you name. Currants and gojis should work OK as well. I don't know about kiwis but most vines are shallow-rooted.

Scott

As Scott suggests, remember to check your drainage before planting. There are few fruiting plants which will grow in standing water.

A raised bed, brilliant! Thanks, that's a great idea. Do you think trees can grow in a raised bed if there's only a foot or so of soil below the bed?

Yes they can but you might need a little irrigation during a dry spell.

The Fruitnut