there are loads of clues about the sequels (it was stated that AC is the first of a trilogy, IINM) hence the achievement name - Visions of The Future. The end achievement also sounds like a milestone/chapter from a book; The Eagle and The Apple - 1191. Eagle being Altair and the Apple being the Piece of Eden. So this means there are adventures to come, most probably a 'prequel'...maybe about subject 16 who left all the clues for Desmond.

Location could be Yonaguni, somewhere in Japan. Interesting...ending a game with clues in the emails.

Oh..and there's a code for the Security Document Department, in Vidic's email. Where do you use this? Or is it for the next game perhaps?

even the 122112 number on the floor refers to the 21/12/2012 date where Mayan propechies say it's the end of the world. Which, in fact is the exact day where Abstergo would 'launch'.