It was available as an option on the Renault Modus from 2004 to 2008, and, as far as I can tell, is an idea that has yet to resurface on any modern car, which is a shame.

Renault’s Modus, just launched at motor shows in Madrid and Birmingham, forms the advance guard for a new generation of small cars. Emphasising space and versatility the five-door Modus goes on ...