Also of interest is that the inventor, John Alexander, submitted a patent application (US5866902), then withdrew the application. Perhaps this was done to establish prior art in the USPTO's database, and prevent someone else from patenting it?
Wow. Stuff like this makes me want to get off my ass and do something cool. Really reinvigorates my passion for hands-on science and engineering, as opposed to the maths and code that I usually look at.
http://dberard.com/home-built-stm/scan-head/