I've seen this video clip a few month ago when it was first posted on BMWs TV website.
Sorry I think there is only a German version of this available.
http://www.bmw-tv.de/tv/automobile/0..._entsteht.html
It takes approximately 10.5 hours and 25,000 parts to assemble a complete 750!
They produce about 300 of them a day for worldwide distribution.