The direct link is here:
http://gundampilotspaz.com/2007/07/1...ndam-in-japan/
And the main source is here:
http://robot.watch.impress.co.jp/cda...07/17/563.html
It really is an impressive project, the fact that a company would go to the trouble of doing this shows you how much Japan respects it's creepy anime nerds.
Unfortunately I could not find the exact dimensions although I looked as hard as I could online. The broken English from the that site once translated by babelfish isn't too helpful. But it seems the Gundam is a small part of a much larger interactive Gundam themed attraction. With people dressed up as characters and they make the it look like you have stepped inside the Anime.
Thanks for the plug!