ASUS has just put out a teaser video that is just ambiguous enough to be anything. What stands out near the end, however, is the word thin, leaving the door open for a new thin tablet, or maybe even a smartphone.
Given ASUS' wide array of products and form factors, and its rather unpredictable release pattern, this could mean anything, from a smartphone, to a tablet to a two-in-one tablet/notebook Transformer, to another PadFone tablet/smartphone hybrid. The latter could be likely since that was already rumored to be in the works after being spotted at the FCC. It could also be a new Transformer that was rumored to sport an NVIDIA graphics chip inside.
There are two things that are quite noticeable in the video, which you can see in its entirety below. The first is the use of a pen to write the message, which could be taken as a sign of a stylus-toting device, possibly a tablet. ASUS has had some before, but the company hasn't exactly capitalized on that feature the way Samsung does. There is also the transformation of the word "thing" into "thin". ASUS' devices have also not exactly competed on the lightweight and thin category, so this could again be new ground for the manufacturer.
Right now, however, this is all speculation. We don't even know yet if it will come in a smartphone or a tablet form factor, let alone if it will be running Android on Windows 8. Computex, however, is coming soon, and ASUS will most likely be telling us all by then.