actually i've seen it, in the Portuguese Institute of Quality (they "supply" the standard cal).
I got the tour. Anyway, it's done in several tubes (3 if i recall, per container) in a aluminium pressure chamber. If that's "hobbyist" friendly, then hell, i really have to move to the US.
http://www.iop.org/EJ/S/0/M32185/pTF...2/9/me7209.pdf
Hmm. Brians : this? Sounds simple. But these things never are.
PS: had my laughts when they used a king size enviormental chamber to test a small pressure device for tyres. The thing is as big as a living room, yet the device is the size of a bread box.