Apple's line of hardware have been going under a pretty steady refresh rate in the past couple of months or so. First came an updated line of MacBook Pros; then came the successor to the first iteration of the iPad, the iPad 2. It seems now it's the iMac's turn to get a refresh.
9to5Mac reports that three different sources -- two from the United States and one from Asia -- claim supplies of the iMac are tightening. One of their sources (who provided them with the above screenshot) says that a constrained amount of supplies for the iMac has never happened during a product's lifecycle, unless a new version was readying for release. The screenshot details that stock of four versions of the iMac are "constrained" and cites that there is no estimated time arrival for more supply.
Their sources also inform them that hardware components for the iMac are also constrained, including processors and hard drives. Other "tipsters" in the U.S. and in an Asian country tell 9to5Mac that supplies are running low in their respective markets.
The last time the iMac line was refreshed was in July of 2010, when they were upgraded with ATI Readeon HD graphics cards. The next iteration is expected to include a Sandy Bridge processor and Thunderbolt, as the MacBook Pro was given in February. No cosmetic changes are expected; CNET's Brian Tong announced a month ago that his sources claimed a new iMac was coming by the end of April or first week of May, and that it should sport the same aesthetics.
The iMac has had a lifecycle of about ten months in the past, as well, so a refresh is expected by this point.