According to BBC's Click programme a Macbook Air type laptop with the facility to turn the cover over so it becomes a tablet was shown at the Vegas Consumer Electronics show will be launched this year.
Lenovo already has one on the market; I was forced to buy one for my daughter by her new school. Touch-screen with tablet features such as on-screen keyboard, but quite bulky.
Professional-Grade Laptop Computers | ThinkPad X Series Convertible Tablet | Lenovo Australia
The EXO PC type of device will be the way to go when the price comes down. Full Windows in a thin "slate".
EXOPC Slate