Mysterious Nokia Lumia with a large screen leaks

What is this? A never-before-seen Nokia Lumia smartphone? Well, it seems so, but we still don't know any specifics about it. As a matter of fact, this might even be a photo of an old prototype model that might never see the light of day, but let's be a bit more optimistic - it might also be a perfectly legit model scheduled for release in the not that far future.

It's assumed that this is a Windows Phone 8-running device, judging by the presence of the Family Room live tile, which is most encouraging. If we take an even closer look at the photo, we'll notice a bottle of water in the background with the word "Pure". Now, we're usually not the ones who'd get too absorbed in thoughts of such conspiracy stuff, but hey, when there's also a Lumia in the picture, the logical thing to come to mind is that it may have some sort of PureView technology!

As we said, nothing is known about this model yet, but it does seem to have a relatively large screen, although we can't be super-sure just by looking at this pic. 

What do you think this could be?