Although I need to note that Jim Plamondon, the inventor and promoter thereof, hasn’t had much luck finding investors willing to bankroll mass production. And it is a shame. A simple version of it would not be very costly to manufacture.

He has been very, very aggressive about promoting his idea. For example: Valleywag, Wall Street Journal, Wired, Engadget, Coolest-Gadgets, and a TV station in Austin TX.
Didn’t anyone tell Mr. Plamondon, a former Microsoft marketing dude, how difficult it is to sell a new kind of musical instrument to musicians? If I were offering advice, I’d tell him to start small. Manufacture a boutique version, get some user feedback. Build the business up slowly, because, trust me, it is the only way.
This IS NOT a mass market. It IS NOT like selling a videogame gadget. Musicians are conservative and spend irrational amounts of time practicing on their existing instruments. Popularizing a new instrument is like invading Russia. Look at Adolphe Sax — he battled other instrument makers in court over patents, and his saxophone did not become popular until well after his death.
Judging from the Wall Street Journal article, which ran six months ago, this is probably a dead issue by now:
“Taking stock of his savings, he says he has about six months left before he’ll have to find a full-time job. At that point the Thummer will be relegated to an evenings-and-weekends enterprise, he says, “and that’s the death of a start-up.””