It still probably needs a few refinements, but I'm hoping to get a little feedback on it before I make them. I did try it out in my shop recently (NYCVelo also has a prototype), and I can confirm that it looks great and works damn well.
The headset is two parts. The top half has two 3.3mm holes "drilled" in it; they need to be tapped M4 in order to make the assembly really work well. I would recommend using brass tipped set screws for aluminum or steel steerers, and nylon tipped set screws for carbon fiber. You can also experiment with thumb screws or plain old socket cap screws if you like.
This may seem like an obscure part, but for anyone who has spent any time handling bike frames & forks, it'll come in *really* handy. If that sounds like you, grab one on Shapeways and let me know how it works!