Cancelled Microsoft Mercury tablet allegedly pictured
While we don't know much about this tablet, it's reportedly called Microsoft Mercury. As you can see in the images below, the Mercury slate kind of looks like a giant Lumia smartphone (we're not exactly sure this is a good thing). There's no word on the features of the Microsoft Mercury, but a camera is clearly visible on the back. We can also spot a front-facing camera, and (if we adjust the contrast a little bit) a pair of speakers at the bottom.
We assume that the Microsoft Mercury was a tablet with a screen of around 7-8 inches (judging by the fact that it appears to be a portrait-oriented device), thus being significantly smaller than a Surface. Or maybe the Surface Mini and the Mercury are (were) one and the same device? Well, we might never find out.