Xperia Blog has just posted some photos it received of a prototype Sony Ericsson phone we've never seen before. The blog reports that it's called the Xperia MT27i "Pepper," and says that it has a 1GHz dual-core processor, a 3.7-inch screen with a 480 x 854 screen resolution, and a 5-megapixel camera with 720p video. We can't tell any of that from the photos, though it does look like a 3.7-incher. What we can see in the blurry shots is what looks to be a secondary mic for active noise-cancellation, a front-facing camera, and an LED notifier. The phone has three capacitive buttons along the bottom — back, home, and menu — just like other Xperia Android phones.

You'll notice that the phone still has Sony Ericsson branding on it, even though Sony made a move to buy out Ericsson's stake in the mobile phone venture in October (the deal's expected to close this month). We think that the Pepper is either an old prototype that hasn't seen the light of day until now, or it's one of the last phones to come from the partnership. If the phone ever comes out, we expect it'll just be in Europe or Asia — American's aren't biting at too many phones with screens smaller than four inches now days. We'll let you know if we spot the Pepper at CES, but in the meantime check the source link to see another photo of the mysterious device.