That's part of why 'm interested in any plants that manage to live more than one season. Ah, just did a quick check and what I want are perennials!

Though I suppose you could try including the root stock in the grafting process...

One nightshade I think I'd exclude from the mix is tobacco. :-)

But the list is fairly impressive:
Eggplant (Fruit)
Tomatoes (Fruit)
Tomatillo (Fruit)
Potatoes (Vegetable)
Goji Berries (Fruit)
Pimentos (Fruit)
Peppers (Bell, Chili, Paprika, Cayenne) (Fruit)

Not on the list I found, but confirmed by looking it up are ground cherries (related to tomatillo)

I think I'd forego potatoes as well, as harvesting them would tend to be a lot more disruptive to the plant.

Trellising might be needed or even that thing where you train them to grow up a wall (espaleired?) But I think a wide bush would be best.

Now one thing that could get interesting is cross pollination between the different branches. Eggplant crossed with Carolina reaper anyone?

Maybe a removable plastic dome thingy would help with over-wintering?

And for once anybody calling it a frankenfood would be *right*. No GMO, just grafting.