The typical 3D printer of today has a rather small build chamber, usually 10 cm, give or take. The more expensive devices have somewhat larger build chambers. Parts that don't fit within build chambers must be broken down into smaller pieces that are manually assembled later.
But an anonymous tipster put us on to a service that can produce Giant Prototypes! Materialise is a service we've seen before, but one of the interesting services they provide is large-scale stereolithography (a laser solid-fuses a liquid polymer layer by layer).
Materialise now has close to ten of these giant "Mammoth" machines, each of which has a build chamber of 2.1m x 0.65m x 0.6m (yes, that's meters!) Currently they can print in two resins with differing qualities.
We especially liked the video below, which shows the entire process from design to completed prototype, including 3D modeling, laser fusion, object emergence and extraction (incredibly requiring more than one person to carry it!)
Oh, don't worry about those guys tearing the object apart with sharp knives at the end ... they are merely removing the temporary support material.