I visited the 2014 New York MakerFaire to support Jetguy's Ulti-Replicator 2 project. It may not be so obvious from the picture, but this is a massive printer - approximately 4 feet x 4 feet x 4 feet -- clearly a very big printer.
However, that printer was eclipsed by the The PartDaddy Delta-printer from SeeMeCNC. The printer measured 15 feet tall.
On the other end of the spectrum, James Carpino built his 1/2-scale version of the PrintrBot Simple, billed as "The Smallest 3D Printer in the Known Universe". The printer sits about 6" tall.
I was able to get the "XL" and "XS" printers together for a photo. Sorry, couldn't get the "XXL" (SeeMeCNC) in the same pic!
BTW, congratulations to Jetguy for earning two Maker Faire Editor's Choice Blue Ribbon awards!