An item in Thursday’s DigiTimes offers an early glimpse at Apple’s (AAPL) plans for its flagship computer line in 2011. The details — based on reports from unnamed “upstream component makers” — are sparse:

• At least four new MacBook Pro models with a “slight” change in chassis design
• A new iMac with a different screen size and a presumably lower price point “for the mainstream market”
• Software upgrades to the new OS X Lion operating system that Steve Jobs introduced at Apple’s  October “Back to the Mac” event
• DigiTimes didn’t specify what chips might run the new machines, but CNET reported last week that Apple is planning to adopt Intel’s (INTC) “Sandy Bridge” architecture, due to be introduced at January’s CES, that puts graphics and the main processor on the same chip.

According to DigiTimes, the new machines are scheduled to ship in the first half of 2011, which would be roughly in line with Apple’s usual 12-month upgrade cycle. The MacBook Pro was last refreshed on April 13, 2010; the 27-inch iMac was introduced on July 27.

Although overshadowed lately by the iPhone and iPad, the Mac still accounts for nearly 27% of Apple’s $65 billion annual revenue. The company’s desktop line enjoyed something of a resurgence in fiscal 2010, generating $6.2 billion on sales of 4.63 million units, up 45% year over year. Apple sold more than 9 million notebook computers in fiscal 2010, up 25% from 2009. According to DigiTimes, notebook shipments should grow 30% to 40% in 2011.

Via 9to5Mac.

[Follow Philip Elmer-DeWitt on Twitter @philiped]