I've got some Burroughs B-7971 Nixie tubes. The glass envelope is ~4.5" tall and the display is ~2.5" tall. Waiting for motivation or a good project. I've got a set of smaller tubes, too, and the TTL-high voltage driver chip.
Heh. I remember being introduced to nixie tubes in the anime Steins;Gate. (If you know, you know. One of the best anime out there.) When presented with a device that uses them, the MC says "Nixie tubes? Someone has good taste."