Lenovo ThinkPad Twist
If you like the idea of the IdeaPad Yoga, but don't like the idea of your keyboard being on the bottom when using it in tablet mode, consider the 3.5-lb. Lenovo ThinkPad Twist. It has the same four-position screen with a 12.5-in. display, but uses a single hinge that allows 180-degree rotation so that the display sits on top of the keyboard.
The Twist also sports features in line with ThinkPad's business orientation: a Trusted Platform Module (TPM), up to 500GB of HDD storage or a 128GB SSD, and a removable battery instead of the Yoga's sealed-in model.