Robohand is a great project for low cost prosthetics and they claim that they operate world's biggest 3d printer far with 53 machines:
http://www.robohand.net/2014/06/robohand-print-farm-the-biggest-in-world/
However LulzBot has a record with 109 machines running:
http://diy3dprinting.blogspot.com/2014/04/world-record-of-109-lulzbot-3d-printers.html
I guess it's not important who is the biggest, the important thing is that the technology is advancing ....
http://www.robohand.net/2014/06/robohand-print-farm-the-biggest-in-world/
However LulzBot has a record with 109 machines running:
http://diy3dprinting.blogspot.com/2014/04/world-record-of-109-lulzbot-3d-printers.html
I guess it's not important who is the biggest, the important thing is that the technology is advancing ....