A little out of date but a huge document here on the IOC Village requirements:
http://www.gamesmonitor.org.uk/files/Technical_Manual_on_Olympic_Village.pdf
See the Chapter starting on Page 60 to see diagrams of past Olympic villages, diagrams of ideal layouts, space requirements for facilities within the village.
This might give you an idea as to why things are done as they are.
Really, as long as the organising committee meets the IOC's requirements there's no limitation on the style of accommodation, but as you can see there are a lot of requirements and it's arguable that
a) It's easier to secure a series of mid/high-rise blocks than a sprawling suburb of low-rises
b) It's cheaper to build accommodation for 16k when you build in blocks.
Another point, which I know is true for London and must be for all host cities, is that athletes musn't have kitchens within their accommodation. Instead a large temporary dining facility is built with all food cooked and served on site. In London's case, after the Games many of the bedrooms will be refitted into kitchens. So whilst London has built enough bed-space for 16k athletes, what we'll have post-Games is infact 3000 new homes.
http://www.london2012.com/media-cen...ns-bedding-in-at-olympic-village-6-month.html
Hope this is of some help.