A previously unannounced 13-inch Sony Vaio slider has cropped up in a YouTube video, purported to be from a Dixons training video.

Although very low in quality, the video shows an Ultrabook with a "Surf Slider" design, as we saw in the Sony Vaio Duo 11, leading us to believe this model will simply be known as the Duo 13.

The latter stages of the video reveal some the features of the new hybrid notebook, revealing 10 hours of battery life, NFC, presumably for simple pairing with devices like the Sony Xperia Z smartphones, a backlit keyboard, ClearAudio+, also found on Sony smartphones, and an 8-megapixel camera.

Of course you get full touch support to take advantage of Windows 8, this being an Ultrabook it houses Intel Core i5 power, 4GB of RAM and a 128GB SSD. A thread on the Notebook Review forums claims that this will have a Full HD display, HDMI, USB, SD card slots. 

When we reviewed the Sony Vaio Duo 11, we were impressed with the build quality, but not so much with the size of the keyboard. A larger 13-inch device may well address some of those issues, but it does beg the question: who want's a 13-inch tablet?

There's no word from Sony at the moment, so there's no insight as to whether we're going to see this in the real world or not.