SubVersion is a cross-platform VersionControlSystem with a FileSystem -like API. Notably, not an installable filesystem with inodes and vnodes that you can go browsing around in a shell and using open(2) and creat(2), but simply an interface that represents the repository db in whatever format as directories with openable/readable/seekable files in those directories. Could probably map to an actual filesystem driver with some work, or back a userland NFS server with much less work.
I am thinking the same thing of doing such a NFS like SubVersionFileSystem. And I want to name it: VFS.
People can benefit from VFS when people working in a FAST intranet environment.