Actually, your theory makes alot of sense. It seems so much more believable now than it did in the 5 minute blurb about it on that National Geographic show.
Jeez...if we starting creating things like this, imagine the possibilities! We have already creating microscopic robots, smaller than the width of a human hair, but they do not yet have the ability to reproduce and construct replicas of themselves.
Check out this site for more on those tiny bots.