What happened to your metadata? Are you sure the metadata is gone?
In theory, file carving could be attempted on the data LUNs, but you would need a tool that understands how Xsan lays out data across LUNs in a stripe group and hope your fragmentation isn't too bad. I doubt such a tool exists, but if one does it almost certainly is not publicly available. You should probably contact a data recovery service with experience recovering data from Xsan. Do that before you do anything else if this data is really important.