The prime example of recent times is Mac Book AIR. It is an example of a nice concept but a poor implementation. That even after being vastly improve with the last update.
Frankly there are a number of ways in which Apple could fail here. One would be to run Mac OS/X on the machine. Another would simply be to make the device to big.
Here thickness is as much of an issue as the area of the screen. If the tablet is much thicker than 1/3" it will have acceptance problems.
Actually I wish Apple would learn from it's mistakes.
Dave
This is why Apple is a billion dollar company, and you are not.
I actually like the MacBook Air. Only problem I have with it is the price. If it was normally $1299-1499, that'd be much better.