Samsung has started shipping it's 500GB 2.5" notebook drive to OEMs. I wonder if this will make it into iMac/mini updates? If so, maybe that's the reason they are waiting to update these macs. just a thought.
http://www.engadget.com/2008/03/09/samsungs-500gb-2-5-inch-drive-arrives-alongside-22x-dvd-burner/
http://www.engadget.com/2008/03/09/samsungs-500gb-2-5-inch-drive-arrives-alongside-22x-dvd-burner/