We were pretty sure we'd see upgraded iMacs introduced at Macworld, but according to the Chinese-language Economic Daily News (EDN) via Digitimes:
.. sources inside the component supply chain as saying that Apple plans to launch a new iMac all-in-one PC in the first quarter of next year, and the company's sole manufacturing partner, Quanta Computer, is gearing up to supply monthly shipments of around 800,000 units durin