Coming out in the begining of 2011, Sony Ericcson Xperia x11 and Xperia x12 are SEs latest offerings in the higherend segment. initially rumoures to be PSP phones they ended up as Xperias.
X11 is the successor to the X2 and comes with Windows as it's operating system - win7 OS to be precise. X12 on the other hand comes with Android probably Gingebread (2.3). The X12 is slated to be the successor to the mighty X10.
The X11 has 1.2 GHz of processiong power courtesy Qualcomm.
The X12 on the other hand comes with a beefy 1.5GHz TI OMAP 4 and comes with UXP customisation and flash support.
They'll be released on the 14th of Jan, 2011.