I'm not one to promote kickstarter projects on a whim, but this one
may be of interest to members in our community. Project OpenBeam is an
open source, low cost miniature construction system aimed at the hobby
and Maker market. OpenBeam is based around the metric system and 3mm
building blocks; to keep the cost of the system low, it is designed
it to use standard M3 nuts and bolts, available at any good hardware
store. No special fasteners are required.
LINK:
http://www.kickstarter.com/projects/ttstam/openbeam-an-open-source-miniature-construction-sys