Apple defaulting the iMac to cheap, slower 5400 RPM drives is scandalous, as is their making the 21-inch iMac's RAM slots non user-serviceable. I've spent a small fortune on Mac hardware over the years, but locking the user out of doing their own hardware upgrades (while charging factory upgrade fees that are miles out of line from market prices) is just naked greed.
"Yes, but the system attempting to mount the Fusion Drive in Target Disk Mode must have OS X Mountain Lion version 10.8.2 or later."<p>Implies that "Fusion Drive" is already part of CoreStorage in 10.8.2. :)<p>That's exciting.
One thing I'm worried about is Linux. The article says you can add only one partition. If you want to install more than one OS, or have separate root, home and boot partitions, what would you do?