Ye Olde Hakka Round-Houses
Hakka roundhouses in the distance. These structures are up to 400 years old.
View from the inside.
Yongding, China, June 2002
Lots of good pics of the exterior and interior of Hakka houses.
A ground floor view.
Yes, people actually live there. Tulou are clan dwellings, so everyone's related.
Clan homes in Fujian
A more technical page with construction details and blueprints and such.
Flickr Tag Search
Flickr has lots of pics tagged as hakka or tulou. If you're really keen, you can subscribe to the RSS feeds (at bottom of flickr page) so you'll be quickly notified if anyone posts more pics.
The Wikipedia page.