Via Lambda the Ultimate comes a hint that maybe things aren't all wrapped up in the world of filesystems. Some researchers at IRISA have designed a Logical File System which integrates the traditional hierarchy navigation model with a query model reminiscent of a logic database. This allows you to perform google like queries within the existing shell framework. It's more than that, though, because the system can perform deductions The authors have built a prototype as a user level NFS daemon. Ehud Lamm says:

The only filesystem that comes close to LISFS in terms of integration of query and navigation was the file system of Apple Newton (so-called 'soup'). But NewtonScript never had any logical inference.

Having worked on the C code that supported soups on Newton, I can say that this is true. The inferencing capability is interesting. It would be interesting to combine some of these ideas with the work being done for ReiserFS. The combination might turn out to be as powerful or more powerful than the database oriented file system that's rumored for Longhorn. I'd like to have something like this to use as a substrate for microcontent experiments.