Lenovo ThinkPad 2
Lenovo's Clover Trail offering is a pure tablet in a 10.1-inch form factor. Yes, you can purchase a dock that integrates a classic Lenovo keyboard, but it's a Bluetooth dock without a physical connector that would turn the system into a traditional clamshell.
The ThinkPad 2 integrates a Wacom digitizer in its 1366x768 display, and includes a stylus supporting 1,024 levels of pressure sensitivity, potentially making it an ideal tool for artists. A USB port is included for external device connectivity. The tablet is 9.8mm thick, but weighs under 1.5 pounds.