Not the carbon itself... Carbon fiber composite structures are highly anisotropic. That's the whole point. They're designed to be rigid with respect to axial loads -- loads in the plane of the fiber sheet. That's why they're such a great fit for uses like panels on the surface of an aircraft or tubing on a bicycle. In neither case is the panel intended to sustain a substantial normal force. Think about it this way... consider the fiber sheet itself without the epoxy component. The fiber sheet is like a sheet of paper -- it has great strength in the plane, i.e. if you pull at the edges. But it doesn't resist you if you hold it at the edges and push down on the center, except to the extent that your axial forces at the edges hold it taut. In the normal direction, for the carbon composite, again you only have the conversion to axial tension and what the epoxy does for you....
In the case of a notebook computer... I don't think it'd be a huge issue. I'm just not familiar if anyone's actually ever made one with a carbon fiber shell and how thin it actually would be.
The thing I wonder about carbon fiber shells... since carbon fiber is so anisotropic, how *thick* are the shells to achieve strength perpendicular to the grain? Thinness seems to be a big portion of Apple's motivation to use metals -- Ti and now Al -- for their pro notebooks. Carbon Fiber would probably be as light or lighter than either... but would it be as thin? The Al shell is what... 500 or 600 microns thick? Should almost certainly be no more than 800.
