This video is on quick statistics on how your food travels etc!
The neighborhoods in 3 hectares can consider Mat Buildings. While you are targeting a density of approx. 33,000 people / sq.km. this website says that Manhattan is 27,485 people / sq.km. And the Kowloon Walled city in HongKong has a density of 1,923,077 people / sq.kms.!
Ofcourse a number of other programs have to be accomodated while these examples look at housing … none the less the comparison helps.
http://landlab.wordpress.com/
100 dwelling units (Dutch canal houses) per hectare. Approx. 3000 houses in 30 hectares. This Project by West 8 is like a neighbourhood in water. Plus other recreational programs have been included
http://www.west8.nl/projects/urban_design/borneo_sporenburg/