Hi Sesuko,
If it's exactly the small glasstube /vial that you're looking for like 'pictured' in the SAS survival book then I still don;'t know a source.
However Traser-UK sells an small "torch like" Beta light and you might try them but be warned these babies cost a lot.
I also found the next story/info at:
http://www.survival-center.com/dl-list/dl27-ret.htm
"BETA LIGHT L3280 - British Pounds 54.95 (appx $US 83.00) "A self-illuminated unit, the Betalight Torch is compact, robust, and has an in-service life of over 10 years. Illuminates well without affecting night vision. This torch works without batteries, light being provided by a glass capsule internally phosphor-coated and filled with tritium gas which activates the phosphor to emit light."
[The editor received his beta light 3-18-96. It is ruggedly constructed and emits a dim green light. There is no on/off switch; there is merely a flap that can be opened or closed. How bright is it? I would compare it to the newer watches that glow green such as the Timex Indiglo. It is bright enough to read a map, find a keyhole, or possibly lure fish. Don't expect to cook dinner or follow a trail with it! My beta light has the following markings: SAUNDERS-ROE DEV LTD HAYES MIDDX UK NATO No X4/6260-00-965-3582 BETALIGHT T19c1]"
Sesuko, I know I once had an address for a simple glass vial type of Beta light but I can't find it right now.
Also Traser-UK can get you much larger glass-vials from the company in Switserland that makes them however these are very expensive and no delivery to the USA.
I'm looking further for you, have a good Easter weekend,
Bagheera