Polytunnel - Exotic and Unusual

Evening,

Planning the polytunnel for next year. I'd like to try a few unusual crops, such as those that are common in S. America & Asia, but little known here.

Thus far I have plumped for Tarwi, a highly productive & high protein lupin and Gac, a delicious fruit similar to Jackfruit. I'm also considering a Passionflower vine, Pomegranate or Strawberry Guava. However, I'm really looking for something a bit smaller, with a growing habit similar to Pepino. I'm also struggling to find anything interesting to put in my remaining three soil beds.

Any ideas?

Plan of the soil beds bellow. The squares are 2X2X2 foot.