The OLPC foundation, which has been credited with originally inventing the concept of a netbook, has unveiled a prototype of a Tablet PC called the XO-3, which it claims will be available for $75 when it arrives in 2012.

It's planned to have an 8.5- by 11-inch touchscreen display with almost no bezel around the frame. It'll have a virtual keyboard and no buttons, a waterproof casing, half the thickness of an iPhone and use less than a watt of power, despite packing an 8GHz processor.

Given OLPC's track record and the weight of those promises, we'll be massively surprised if the project comes to fruition. The original XO has never sold for less than $172, despite promising a $100 laptop from launch, and the XO-2, originally due in 2010, has completely disappeared off the face of the earth.

So colour us sceptical, but we'll keep you posted of OLPC's progress.