The perfect Backup and Synchronization Tool

ideas tagCC Creative Commons - Photo by Topato/Roadhunter - Flickr Source: the “perfect backup and synchronization tool”.
[*] synchronize and/or backup selected file sets
[*] unlimited revisions (version history)
[*] support central servers and/or decentralized client exchange (“peer to peer”)
[*] support to backup to external drives, including the full file history
[*] work offline and still have a version history
[*] local revision history is automatically distributed to all participating clients
[*] transparent
[*] automatically monitors/tracks changes and immediately sync in the background
[*] (alternatively, eg. for files that are constantly changing (email database), do scheduled or manual syncs)
[*] if network/other clients are available, sync with them (including file history)
[*] if connected to selected external drives, auto-sync to it
[*] safe encryption on all clients/servers (both storage and transfers)
[*] of course, only store and transmit incremental updates (deltas)
[*] “traveller mode”:
[*] web interface to download individual files from any revision
[*] sync complete set of files from a specific date/revision without admin rights
[*] open source, FREE
[*] platform independent
[*] independently scalable to “unlimited” clients
To get the idea, compare with [url=]Dropbox and Syncplicity[/url].
Sounds too good to be true? It does exist (well, sort of) ! [url=]See my wiki for details[/url].