Dell is pulling back the curtain on the XPS 18, its new portable all-in-one. This machine is a natural competitor to the Sony VAIO Tap 20, with a built-in battery (rated for five hours of runtime) and a similar design that can transition between traditional desktop mode and lying flat -- in this case, thanks to flip-out feet on the rear side of the device. With an 18.4-inch, 1080p display, the 4.85-pound XPS 18 makes for a pretty enormous tablet, but we're talking portable in the sense that it can tag along on business trips and move from office to living room every once and a while. The all-in-one will come with a Bluetooth keyboard and mouse when it debu
