According to Appleinsider, Apple may be planning on nixing an optical drive in its next round of updates for the iMac and Mac Pro. Apple has clearly been heading towards a cross platform rule of no optical drive inclusion, with the MacBook Air, Apple TV, and MacBook Pro with Retina as the pioneer devices to lack the dying disc reader.
When reviewing internal configuration data in Apple's new OS, Mountain Lion, files made reference to unreleased iMac's and Mac Pro's, possibly not containing an optical drive. Boot Camp Assistant holds internally a configuration list file that names by initial and its Apple designated architectural version ID, the Mac models that are able to support a boot disc or a USB flash drive that can install windows to a Boot Camp partition.