It is technically possible to run on 7 hours of sleep, though you would probably always be tired doing so much work on that much sleep.
I wonder if it's possible to find a place that would hire people to work 24-hour days. They could sleep when there are no customers there and just hook up a pair of headphones to an amplifier so that the *DING* from the door when somebody walks in will wake them up. It's a perfect scheme to make around-the-clock pay >=)