Why doesn't someone just drop the word that the move will be nearby and let scuttlebutt do its job? Wouldn't be too hard to reassure someone without getting caught.
Come to think of it, why does the company need to move at all? If you're in Fredneck, it's sufficiently close to DC that there has to be demand for office space. No chance you can split the space (within code requirements) and sublet say 50% of it?
(OK, maybe that won't work if you work at the Anthrax Lab at Fort Detrick.)