I found a post on CPF that mentioned these. A U.S. supplier actually sells different sized tritium "safety markers". Not quite as snazzy as trasers, they may actually be brighter. I know the two larger sizes are bigger.
Tritium Safety MarkersI've ordered one each of the smaller two sizes. Assuming they actually ship (a confirmation is not the same as having the merchandise in hand <img src="/images/graemlins/smile.gif" alt="" /> ), I'll follow up with a review.
Possible uses? I think they'll be great to use on things like bug out bags, light switches, etc. Anything you'd want to be able to find in the dark.