I worked at a Pizza Hut in college that had one that washed a full load of dishes in just a few minutes. I'm blanking on the exact time, but I'm almost certain it was under 10 minutes. It got extremely hot, so it probably wouldn't work for a lot of dishes people have at home, but it was very efficient! We saved at least a few hours of labor a day from it, and an unquantifiable amount of sanity.

It wasn't designed like a normal home dishwasher, it was open on all sides and you would slide a rack of dishes under the top part of it, pull a lever, and the dishwasher walls would come down around it and start the washing.