Joystiq is reporting that a document has been found on Scribd (now removed) detailing the plans for the next-gen Xbox through 2015. They seem to think that the document was created sometime in 2010, the same year in which the Xbox 360 Slim was released.
Details covered in the PDF include: Blu-Ray, 3D ouput, XTV compatiblility, multiple 1080p in and out, stereo Kinect V2 (depicted as two units mounted on either side of your TV), AR glasses that can be used outside the home as well as in-game, the ability to play your new Xbox console games on any device, Windows 8 foundation, clip-art and poorly rendered people having seizures.
And while all of this seems entirely plausible and even matches up with several rumors, the mystery document also claims that the target price for all of this is a mere $299. To me, this is the most outlandish part of the entire document. For reference, the Xbox 360 launched in two flavors, the highest of which was priced at $399. Perhaps $299 is the price of a cheaper configuration once again.
Note: Covington & Burling LLP have removed the original leaked document from Scribd. The law firm has worked with Microsoft in the past.