Model on Shapeways:
1) six membered tetrapod ring
2) single tetrapod

This is a tetra-pod made mainly out of carbon atoms in tetrahedral sp3-hybridization. That means the part has the same symmetry as the atoms it is made of.
The surfaces are passivated (plugged) mainly with Hydrogen (white).
to make the surfaces chemically unreactive.
Some sorts of productive nano-systems like nano-factories will be needed to produce / "print" objects like this.

Nomenclature

The abbreviation DMSE stands for:
-- Diamondoid Molecular Structural Element
which translates to:
-- very stiff and crystalline -- very small -- non active non moving -- building block

This acronym is rather unsuitable for use in natural language so I'd like to advertise the portmanteau: "crystolecule" for building blocks of this kind. It seems fitting since they are small like molecules but their interior has a dense three-dimensional polycyclically meshed and ordered structure like a crystal.

Details

This structural crystolecule is meant to be used in bigger frameworks like nano-housings etc. The strut ends are unsaturated Surface-Interfaces.
The seven open bonds can be put together in two different ways.
Thus when assembling the tetrapods beside "normal" diamond structure also lonsdaleit structure & many more are possible.

You can find more technical information about
mechanosynthesis and atomically precise manufacturing in general on my website:
http://apm.bplaced.net/
or in the book "Nanosystems" written by Eric Drexler.
http://e-drexler.com/d/06/00/Nanosystems/toc.html

Titlepicture made with:
QuteMolX, v.0.5.1, Nanorex, Inc., www.nanorex.com, 2010.
http://qutemol.sourceforge.net/
Structure generated with:
NanoEngineer-1, Nanorex, Inc., www.nanorex.com, 2010.
And the paper that presented QuteMol:
Marco Tarini, Paolo Cignoni, Claudio Montani: Ambient Occlusion and Edge Cueing for Enhancing Real Time Molecular Visualization, IEEE Transactions on Visualization and Computer Graphics, Volume 12, Issue 5, Pages 1237-1244, 2006, ISSN: 1077-2626

Related

Somewhat related to this is one of the simplest possible structurally usable 2D fractals: http://www.thingiverse.com/thing:14023 .
Extruded this would form some spongy hexagonal tube structure.