Good to hear like Duplicati!
Unfortunately, I’d have to say it’s VERY far away (as in maybe never) from being able to do a full drive image backup. This is due to the underlying way that Duplicati has been written to handle file changes.
File level access is fairly straight forward in that it’s all built built into .NET and Mono. Duplicati doesn’t have to know anything about how a disk is formatted - it just says “give me file X” and .NET / Mono does provides it.
To get access to disk (rather than file) level data would need an entirely different set of functions that would probably work very differently on different operating systems. While they could possible by added to the existing code, Duplicati would have to change what is stored in to backup to keep track of not just what blocks of data belong to what file, but also physically where on the disk those blocks are stored.
So, sadly, it’s not a minor jump to go from file backups to drive imaging.