Sony Ericsson Xperia SK17i Mango that runs Android 2.3 leaked on a Chinese forum. This is the successor of Sony Ericsson Xperia X10 Mini Pro launched last year which also has a slide out QWERTY keyboard.
As you can see in the picture, this phone does away with the three key layout in Xperia X10 pro and comes up with a single home button and touch sensitive buttons.
Sony Ericsson Xperia SK17i code-named Mango is said to have 800 Mhz or 1Ghz Processor, Qualcomm MSM7230 CPU with Adreno 205 GPU, 3.2 inch 320 x 480 (HVGA) capacitive touch screen, 5MP camera with flash.
This phone has already been leaked twice once last December and again this January. This phone was expected to launch at MWC this February but no news on the release date yet.