Don't know if its of interest - but some of Vaultsters capabilities can be achieved through nwnx_odbc and a MySQL db.
MySQL allows for Load From and Save To commands - allowing saving to a file system.
If both servers were pointing/connected to the same DB, or had a way to get the binary data (web service?)
They could save the bic file (SetPersistentObject()) to the Hard Drive from the database, and then on join - access their transferred bic.
A Heartbeat could check the file contents of the bic files against the content in the database, and do the Save To conditionally based on whether they match.