My plea has been answered by a DVFS project specification. For some strange reason, my edits do not show up in the freedesktop.org wiki page and the blog of its creator is not reachable, so I post it here.
I am very interested to help develop this tool and then use it in Simple Backup Suit (sbackup). An additional feature that I would love to see is automatic splitting of a file into several chunks. In an ideal work it would be possible for me to get (in Python) a filehandle-like object that would compress the data (gzip/bzip/..), encrypt it (with simple encr. or gpg style), transfer it over network (ssh/ftp/dav/smb/...) and then split into 100 Mb pieces on the remote server (to overcome possible max filesize problems with 10,50 or 100 Gb backups). And have the freedom of flexibility of activation of each element of this chain when creating the file handle. Also the interface must react in exactly the same manner regardless or the backed being user (for example opening non-existing files must always rise the same error).