As Sony Ericsson gets ready to show off its gear at the CES, one of the banners the company has produced for the show reveals a mysterious sliver of a phone, possibly one of the thinnest we’ve ever seen.

The most revealing aspect of the image is that black spot on the phone’s side. Taking a close-up look, it appears to have a beveled edge leading into an open cavity. Call us crazy, but that looks like a conspicuous headphone jack. Keeping in mind that a headphone connector is only 3.5 millimeters wide, and you can appreciate just how thin this Sony Ericsson model is.

Sure, there’s the possibility that we’re not looking at a smartphone at all, but the upper half of a flip phone. We’re keeping an open mind, but if that’s the case, Sony chose an odd location for that headphone jack.

We know there are a bunch of new Xperia models that Sony Ericsson has lined up for its MWC appearance; could one be making an early showing here? While we have our theories about what some of the lineup may be, we haven’t yet found a phone to go with the “Xperia Duo” name the company has trademarked. If this is that phone, the “Duo” label has us thinking: dual core? Could be. A phone with a focus on entertainment, as the advertising describes, would certainly benefit from some extra processing muscle, especially if working with HD media.

Sony’s planning a press event for tomorrow evening, where we may get the skinny on this phone (no pun intended).

Update: There’s a lot of talk going around right now that this may be the Xperia Anzu, not the Duo. We’ll admit that it’s close to the leaked Anzu pics, but something still looks a little off. Judge for yourself:

Source: Engadget, Mobile Review