According to the creators, it was hand-dug (well they used pickaxes, but no explosives), the map is 16000 x 16000 blocks, 10 million blocks and they currently have no plans on releasing it to the public. It took hundreds of hours to make it with over 40 volunteers and rendering map takes 2-3 days, it also won several rewards in worth1000. The world is on one of the more prominent pay-to-play servers (part of GodCraft) although I do not know which.
Funfact: they wanted to fit in balrog but it was too large to fit in scale. The project was started before the change to height so they would have had to terraform the entire mountain up to sky level. Pic for reference:
[Image: http://i.imgur.com/8Oghq.jpg]