The new iMacs may not be home for Christmas. Via AppleInsider, French blog MacBidouille reports that Apple’s new iMac all-in-one PC models will not be ready for sale by the holiday shopping season. The blog speculates that Apple is having supply-chain difficulties, as its manufacturers are struggling with an “advanced welding process.” The new iMacs are quite an impressive fete of engineering, with edges that measure in at just 5 millimeters thin despite having display sizes of 21.5 inches and 27 inches. In other words, it’s not surprising that they’re challenging to mass produce. Read the full story at Boy Genius Report.