Apple's wild success with unibody construction for all models of the MacBook appears to be having a negative effect on the competition in more than just reduced sales -- the other vendors can't get their hands on the CNC (computer numerical control) lathes that are required to make ultra thin magnesium-aluminum shells to encase the electronics of Intel's UltraBook design guideline.
According to Taiwan-based electronics industry site Digitimes, Catcher Technology and Foxconn Technology both have more than 10,000 of the expensive CNC lathes used to make notebook chassis. These two companies are major suppliers to Apple, which means that companies wishing to make metal UltraBooks have to compete for capacity on those lathes. That's a hindrance to high-capacity production, so many manufacturers are choosing a different material.
For the competition, it looks like RHCM (rapid heating cycle molding) based fiberglass is the solution. The fiberglass is mixed with plastic to create a material that is both tough, moldable, and lightweight, and the material is also about US$20 cheaper per laptop than the more expensive metal. While that doesn't sound like much of a cost reduction for manufacturers, it boils down to an end-market price that can be as much as $100 cheaper.
The main beneficiary of the competition's move to the RHCM plastic-fiberglass composite is Taiwan-based Mitac Precision, which apparently has the yield and production capacity to keep the UltraBooks flowing.