It never shipped obviously, but back in the day there were a lot of rumors of Apple developing a feature that let you take your home folder and apps with you on your iPod, with any Mac you plug it into making your user account available without even rebooting. So it seems that they saw that use case and almost acted on it.
Unfortunately the oldest snapshot in Wayback is October 12th 2003 with the blurb already removed. Apple filed a patent application for it in 2002 which was assigned in 2006. It expires this year!
Surprisingly, there have been a few vapourware announcements by Apple over the years. Another was the “Restart to Windows” item under the Apple menu when Boot Camp was first announced.
Would love to have been a fly on the wall after the keynote where Steve chewed out the engineer that left that in.
