http://opensourceecology.org/gvcs/
They've re-invented the tractor and 3-point / PTO implements, but they've done so very VERY poorly, there are no instructions, everything is hand-wavy, etc.
It's condescending bullshit by "designers" who want to help third worlders with no realization that the best approach for an actual third worlder is to buy a used / discount version of the commercially available product.
For example, their cement mixer design is 25% done (whatever that means), and is going to cost about $1,000 in parts alone, or $1,800 in parts and labor.
Here's one that attaches to a tractor for $900 http://www.northerntool.com/shop/tools/product_200660639_200... and you can find similar items even cheaper on Alibaba.
A lot of these "let's help people farm!" websites are made by people who don't know anything about anything but seem to be compelled to do something so that they're "helping".