The materials are called Frosted Detail and Frosted Ultra Detail. Frosted detail boasts 0.1mm clearance for moving parts and 0.5mm minimum wall thickness. And Frosted Ultra Detail promises a very impressive 0.05mm clearance and 0.3mm wall thickness.
My first model for the Frosted Detail has been ordered! It's a little WIP Tesla Defense Tower for 1/1200th scale Victorian Science Fiction tabletop wargaming, and designed in a similar style to Spartan Games Dystopian wars models. The model linked to above has several parts sprued together, for easier painting prior to assembly.
The completed model will look like the model shown here . I've ordered two, one in Shapeways regular White Detail and the other in Frosted Detail for a side by side comparison.
Squid!

Another model in the same order, in Frosted Ultra, is a Small Kraken, this one is my Kraken, scaled down to half the size.
All being well, the models should arrive by the end of next week (May 6th).
More squid!
Frosted detail and Frosted Ultra Detail are both transluscent/transparent, and the support material is a white coloured wax. A while back, I created a model using the Kraken above, scaled down to 18mm and place inside a solid block. I called this Kraken in Crystal... so I took the same model and scaled it down even further Kraken in Crystal - small.
Funky stuff

Little stuff.

And now the finale...
The current world record for the smallest working Rubik's Cube stands at 10mm... with this little beastie, I'm aiming at 6.2mm! Each side of the cube comprises of 9 2mm squares with 0.1mm spacing. The mechanism design is more-or-less the same as the original patented Rubik's Cube, so even if the cube is printable, I won't be able to offer it for sale.