I just read an article in the newspaper about Schoonschip, a floating co-housing in Amsterdam. It includes 46 households or more than 140 residents.
Below you can find a picture that gives an overview of what they realised. Personally I’m very impressed with their environmental efforts, which include vacuum toilets, showers that reuse their own water, a smartgrid etc.
They have a very comprehensive website describing their project, and they also have a rather detailed manual-like website called Greenprint that includes some lessons learned.