It took Apple months to catch up with the demand for its most recent iMacs, but now they’re finally in stock. So what’s next? VESA mount support. Neither the 21.5” or 27” models can actually be mounted when purchased as is—a limitation that affected the prior 21.5” iMac as well. To address that issue, Apple has today released both 21.5” and 27” iMacs with Built-in VESA Mount Adapter (Late 2012) ($1339-$2039).…