Haha. +1 for the effort (though my pedantic affectations force me to note it's `BeOS' rather than BE/OS).
Plan 9 had some brilliant ideas. In addition to the whole Acme editor being integrated into the OS at levels which beat out even Smalltalk, and the Plan 9 tags(1) [see: File indexing and searching for Plan 9] system was marvelous as well. I've been trying to come up with a semantic information modeling system better than the standard hierarchy, and better than just a tagging system. tags(1) and Lotus Agenda get(got?) pretty close.
Side-note: emacs org-mode users - I highly suggest experimenting with Agenda in DosBox for a few months. It's pretty much the paragon of PIM, so much so that I wrote a few thousand lines of elisp to replicate most of the functionality.