From kernel help page for Coda
Coda is an advanced network file system, similar to NFS in that it enables you to mount file systems of a remote server and access them with regular Unix commands as if they were sitting on your hard disk. Coda has several advantages over NFS: support for disconnected operation (e.g. for laptops), read/write server replication, security model for authentication and encryption, persistent client caches and write back caching.
Coda File System
If you decide to use it please come back and tell us how good it is.