If your holiday shopping list includes one of Apple's refreshed iMacs, you may want to start working on a backup plan. According to a "commercial source" speaking with French blog MacBidouille, the updated all-in-ones may not hit shelves until early next year due to manufacturing complications related to the 5mm edge thickness of the mounted display/chassis -- 80% thinner than previous generation models.

This reduction is partly achieved through a friction-stir welding process that uses heat and pressure to adjoin two aluminum surfaces, enabling seamless joints between chassis sections. MacBidouille notes that this method is used in other fields, such as the construction of aircraft wings, but apparently computer makers are less versed in the tech or the new iMacs are simply that complicated to build -- or both.

It's also believed that Apple's manufacturers are having trouble with producing the iMac's new displays. The screen is 45% thinner than what's inside last year's models and it uses a lamination process that eliminates the 2mm air gap between the panel and front glass. This approach increasingly common among smartphones and tablets, but it's reportedly harder to accomplish with the iMac's larger screens.  

We'd usually hesitate to run a rumor like this and we still recommend you take the news with a grain of salt, but recent comments from Apple suggest that things may not be going smoothly with its latest all-in-ones. During a conference call held a few days after Apple's October media event, CEO Tim Cook warned that the company was facing a "significant shortage" of the new iMacs through the fourth quarter.

Apple has declined to comment on MacBidouille's report and the company's online store still shows the original launch dates of November and December for the 21.5- and 27-inch iMacs. In a less extreme prediction, a person familiar with the situation told CNET that the 21.5-inch would probably be delayed until next month, but that both models would still ship in time for the lucrative holiday shopping season.

Along with their new complicatedly-thin design, the new iMacs introduce a hybrid storage technology that Apple calls "Fusion Drive." The 21.5-incher will start at $1,299 with a 1920x1080 IPS display, a 2.7GHz quad-core Core i5 CPU, 8GB of RAM, an Nvidia GT 640M GPU and a 1TB HDD, while the base 27-inch version upgrades that to a 2560x1440 screen, a 2.9GHz quad-core Core i5 and a GTX 660M for $1,799.