Plan 9 OS has something like AmigaOS multi-assigns

Given how useful assignments (and multi-assignments) are on AmigaOS, I was interested to find that the Plan 9 OS implements something that is conceptually very similar - albiet done in a Unix way.

http://en.wikipedia.org/wiki/Plan_9_from_Bell_Labs

If you look at "Union directories" you will see that it allows several directories to be 'overlayed' on top of each other (in a new location), in a fashion very similar to multi-assignments.

Thus they can have "/bin" for binaries actually stored in many different folders, much like we can have "C:" point to multiple folders (if we want).

They don't bother using "search paths", but instead use Union directories for that purpose. I wonder if AmigaOS could use multi-assignments to replace paths? (One difference would be that multi-assignments are global, where-as paths can be local... I think that would actually be an improvement.)

Maybe a fork of the open source alt: "Union AROS"