So far, we've seen three Windows Phone designs out of Nokia: two colorful renderings from February and the more recent Sea Ray (and actually, considering how similar they are, the Sea Ray might just be the real-life execution of those early renders). A fourth one seems to have been leaked out in a video posted on YouTube in the past few hours, bearing a pretty strong familial resemblance to Nokia's Symbian-powered C5-03.
I believe this is real -- but I also believe that it's a pure concept put together by Nokia around the same time as the first official concepts that came out early this year, possibly as part of a presentation to investors or carrier partners. There are a few hints of that. First off, one of the other concepts makes an appearance in the same video around the 0:28 mark, and I'd be surprised if they were still showing those internally. Second, the device uses an old pre-Mango version of Bing -- it's only got three buttons along the bottom, whereas Mango's got four. Third, as MyNokiaBlog points out, there's an Ovi tile; considering that Nokia announced it was changing the name of its Ovi services to Nokia services back in May, a new video certainly wouldn't be touting them as Ovi.
That said, the connection to Nokia's existing design DNA is strong here, so I wouldn't be at all surprised to see a device like this launch down the road -- possibly atop the rumored Tango release of Windows Phone. For now, though, I'm chalking it up as an official render -- nothing more, nothing less. What do you think? See the video after the break.