There have been some nice experiments to make a wiki behave more like a filesystem:
*[Integration of webdav and JSPWiki|http://codinginparadise.org/weblog/2004/08/i-added-webdav-to-open-source-wikiwiki.html]
*[FUSE filesystem for mediawiki|http://wikipediafs.sourceforge.net]

[FUSE|http://fuse.sourceforge.net/] is a promising technology available on most *nix platforms (works on [MacOS X|http://code.google.com/p/macfuse/], Linux, FreeBSD, [OpenSolaris|http://hub.opensolaris.org/bin/view/Project+fuse/]) 


There quite a few obstacles in the way of a seamless solution:
* Windows seems to have made webdav optional
* Firefox does not know how to handle dav protocol and Gnome does not allow to follow the links if the webdav is not already mounted.