I've been making bonsai out of my pepper plants as a way to overwinter them for a couple years now while I waited for my main project to grow big enough to cut back (a eucalyptus gunnii, which I cut back a week or two ago, its doing fine).

I like that my bonsai have more uses than being purely ornamental. The bonchi (bonsai chilies) can and do produce pods while being bonsai, I've got a blueberry that I've trained into a bonsai, and I'm considering getting an actual tea plant (camellia sinensis) to make into a bonsai as well. All of which produce fruit or edible leaves.

What other ideas are there for bonsai that will produce fruit or other useful bits? Main issue I see with most of the trees/shrubs that spring to mind (mulberry, cherry, even a grape vine) is that they have very large broad leaves. Not exactly ideal for a bonsai that you want to keep producing.