I just received my new issue of
Dwell and there was a fantastic deli inside, the Taylor Deli in DC. It's very modern and rustic with boards used as both a wall treatment and counter material.

Then the search led to the Story Deli in London which is a different sort of rustic modern design and has stools made of repurposed cardboard packing boxes which I absolutely love! (This picture is hard to see, but a better one is
here.)

I can't imagine the boxes would be comfy to sit on long term but for a slice of pizza they would probably be fine.
{top photo: jsmjr, bottom photo: Marco Cadena}