Not an official taxi service, but rather a private cargo bike of someone feeling that way. After roaming the internet, I found out it is a Bella Bike, invented by a Danish blacksmith 10 years ago. The Bella Bike web site is in Danish, but if you feel compelled to know more, I did find an elaborate post about it over at Copenhagenize. One of the popular selling points is that you can have the box custom designed. Although I can't really see anything top this one.