Implement a limit on the amount of space consumed on remote storeage

I have been backing up via SSH to a remote machine, that is shared with other users.
It is possible for a single user to consume all the space on the remote store, preventing others from successfully backing up.
Being able to place a limit on the amount of space consumed would be a great idea.
The first step would be to allow this to be set in the either the "Storage" or "Schedule" configuration screens.
Ideally we could find a way to set the limits for each account on the backup server. Perhaps issuing a command that can determine a directory quota.
Right now I limit the disk usage by loop mounting a file containing an EXT file system as the directory specified Deja Dup.
The size of the EXT file system set the limit for the space used.
I can then use the file system tools to expand/shrink the file system image as necessary (very painful)
This why I would like to see the limit set in Deja Dup.