At Edd's blog there is mention of Novell open sourcing their VFS and the possibility to integrate it into GNOME. Very interesting, I should add support for mounting Simias to libferris hopefully sometime shortly after they release it. I suspect it might be somewhat hard to install Simias at first though (maybe they want to beat libferris for difficulty to install ;)
Does make me wonder a little about the whole 'sharing VFS' thing that comes up from time to time (search freedesktop.org's mailing lists). As to, at the level of an Extended Attribute extractor (like something that extracts EXIF data from exif/jfif images) whether there can be code sharing. I think this is the most realistic level where the VFS systems can interoperate as there is an EA interface and a binary chunk that data is extraced from. Though even at this 'grass roots' level libferris differs from C based VFS systems in that data is accessed through the C++ IOStreams interface... though bolting a obj->read( offset, count ) to that should be trivial.
On the flipside, I've been adding support for Adobe's XMP metadata embedding to libferris. This should make for a reasonably kickass /usr/local/doc search engine with the new EA from pdf files and the fulltext indexing of HTML and PDF etc that ferris already does. I think I've managed to sniff out most of the embedded RDF standards now, after XMP there is the jpeg COMMENT1 block RDF standard that I've yet to code support for.
I might have to make mod_ferris for apache soon so that a web interface to the EA/indexes can be created... maybe.