Hi,
Thinking back to my child hood there was a children magazine that had a pack of seeds for baby eggplant in it. Those should be also growable in one of the smaller gardens.
Another idea is baby bell peppers. I tried already the spicy ones (not that spicy for my taste) but why not going all the way to have some sweet baby bell peppers?
Mini cucumbers or Gherkins would also be an idea.
CU Assetburned