These would make an interesting platform for building Gadgeteer projects. The pieces screw together using slots. So, hole spacing isn’t much of an issue. Kinda like heavy duty aluminum Erector kits.
http://makeblock.cc/features-of-makeblock/
They’re selling them at Seeedstudio. A bit pricey but they do look like high quality.
http://www.seeedstudio.com/depot/index.php?main_page=advanced_search_result&search_in_description=0&keyword=makeblock+kit&x=0&y=0