Yes it's all a sculpt, he even sculpted the dress and clothing folds for everything in the scene.
One forum member sums it up perfectly in the comments section;
"Hello, I'm a newbie and this is my first post. I'm gonna destroy your brain with my insane work and get Top Row instantly!!!" Muah ha ha ha!!!" - remcv8
You can view the actual image in full detail here.
The next coming version of ZBrush, 4R7, will be the last update until the release of ZBrush 5, in which they move over into 64 bit. The coming upgrade offers an amazing new polygon box modeling workflow that takes this sculpting software into a new place, such that you might opt to do all your hard surface modeling within ZBrush from now on. I'm looking forward to it.