solidify is a remote, cached, synchronising FUSE filesystem. It is written by Jan Essert and released under the GPL.
It is meant to provide a partial local copy of a remote directory as well as synchronisation. In a way, it will be a mixture of sshfs and of the excellent unison.
More precisely, solidify will crawl a remote directory and display a ‘ghost image’ of this remote directory when mounted. Upon accessing files in this directory, solidify will try to copy them via ssh in the background or, if the remote computer is not available, mark the files for later retrieval. In any case, the user can then modify any file which is solid, i.e. locally availabe.
At any time, the user can invoke a synchronisation, which will update the both filesystem’s idea of the remote directory, as well as apply any changes back to the remote site. This synchronisation could also be done in the background, at a later time.
Currently, solidify is still under development and not useful yet. For an overview of the current status, see the development page.