Another fruit that goes hand in hand with chilli is Tamarillo or tree tomato.
Works best if tamarillo dominated with a fruity spice added to taste.
Caped goose berry is another.
Just thinking out loud
Some interesting thoughts there Smokey Mick.
Your post got the wheels spinning in my head, especially with your idea of using tamarillo, which comes from the same family of plants as the chile pepper, namely the Solanaceae family.
The Solanceae family provides many important food crops, but it also contains plants which have a dark side, the deadly nightshade plants.
Some of the nightshade plants are not only poisonous, but also very psychoactive and hallucinogenic, when used in very low concentrations, thus giving them the names 'Witching Plants' or the 'Hexing Herbs'.
Now since I've noticed a lot of reference to the occult or supernatural in hot sauce labels, such as the words, 'Devil', 'Evil', 'Ghost Pepper', perhaps a 'Witch's Brew' could be concocted out of the harmless, edible members of the Solanceae family.
Some of the plants to choose from might include: eggplant, sweet potato, tomatillo, tamarillo, tomato, sweet pepper, hot chile pepper, wolfberry or goji berry, to name a few.
For more information on edible Solanaceae plants for a so-called 'Witch's Brew', check out this link on Amazon:
http://www.amazon.com/Edible-Solanaceae-Wolfberry-Aethiopicum-Naranjilla/dp/1156809991
Just me thinking out loud also, but maybe some food for thought?
dvg