Intermezzo was started by one of the developers of Coda, with all the same goals, along with the goal that accessing files shouldn't be any slower than using a local file system (since they are cached locally).
Intermezzo is available from Intermezzo?, but has been abandoned since 2002. The developers from Intermezzo are now working on Lustre, but Lustre seems to be focused on large network clusters and disconnected operation wont be available until v2.0. Seems Coda will be the way to go.
4 pages link to Intermezzo:
