A developer made the mistake of blabbing about a Microsoft event on Twitter, claiming he was having a great time at the "Durango developers summit" in London. Given Durango is one of the suspected Xbox 360 development names, that would appear to be confirmation that Microsoft is in the midst of publicising its new Xbox plans with game makers.
The developer was and maybe still is in the employment of Crytek, which has long been rumoured to be working on a launch title for Microsoft's Xbox 720 or whatever it ends up being called on release. The tweet, since deleted, said: "Enjoying the Durango developers summit in London. So far, great swag and interesting talks."
The codename Durango doesn't give us much of a clue about the hardware. Durango is, among other things, the name of a Mexican state, a shoe company, a local newspaper and a type of car. Which sounds more like a Nintendo console. [The Verge]