DA's backup user feature (Reseller Level) will do part of this. It can run as a cron on the date you specify (or whatever.. daily, weekly, etc..) and can transfer the file to an ftp. It will not create a date directory though. The system backup creates a date directory, but not the user backup. You would have to create the date directory by hand prior to the backup and then put that directory in the DA User backup ftp settings.
