Sounds like a Nixie tube.
(http://bulbmuseum.net/nixiecounter.jpg)
Though not made for a good many years now, the tubes are still available. To buy some, simplest thing would be to search Ebay for "nixie tube". Several of the later versions made in the former Soviet Union are commonly found and not too expensive. You can also often find Nixie driver boards and parts of old test equipment like that counter board up there, which can be used as the basis for clock designs. And there is a load of information on the tubes and driver circuits out there, here is just one page with details on building a simple AC-driven clock (http://electricstuff.co.uk/nixclock.html).
:)