A new Apple patent uncovered by PC Pro hints at the possibility of portable user accounts making their way into the Spring '07 release of Mac OS X 10.5 Leopard. For a quick break down: the long-standing rumor has been that this would allow a user to keep their account - the entire home directory, applications, media, preferences, you name it - on an external storage device like an iPod, and simply plug that device into any Mac and log in with access to all of their stuff. The possibilities are pretty juicy, and for once the language in the patent is fairly straight-forward, if not a little repetitive: "The multi-user computer system, eg. through its operating system, locates user accounts not only in local storage of the multi-user computer system, but also in any removable data storage attached to the multi-user computer system."
While this particular rumor has been in the wind for a few years now, we don't have anything else specifying that it is for sure arriving in Leopard. This could be yet another unused patent, or it could be slated for 10.7 for all we know. As usual, we'll keep our ears out.