Update: You can find more details, pictures and videos in this article.
It seems Sony Ericsson is preparing for a big announcement at CES in Las Vegas. A billboard in Las Vegas suggests a new announcement is imminent and some sources say it may be featuring the previously rumored XPERIA X12 a.k.a. Anzu.
Interestingly, according to SEMC Blog, the X12 will be called XPERIA Arc and will pack 4.2-inch multi-touch X.LED screen with 854x480 resolution, 8 megapixel camera using a Sony Exmor R back-illuminated CMOS sensor, a full set of connectivity options (incl. HDMI). We have no clue what exactly X.LED is, but it's good to see Sony Ericsson is about to jump on the LED technology.
The XPERIA Arc should be only 8.8mm thin, so it may easily become the slimmest smartphone up to date.
Here is another teaser picture from SEMC Blog:
CES 2011 officially starts tomorrow, so it won't be long until we see if there will be an announcement.