Is the Lumia 900 a real device or an Arctic mirage? We've seen repeated clues that Espoo might be working on a bigger Windows Phone to complement the Lumia 800 and 710, to the point where the strange Twitter conversation above doesn't strike us as totally surprising. A customer named Xavier Hahn tweeted support staff at Swiss operator Swisscom, to ask about a timeline for the "Nokia Lumia 800 or 900." Apparently forgetting that the 900 is an unknown
