Secondary backups using sign-in-as-user via API

We're looking for a way to make a backup of all our Dropbox business files on local machine. Currently, the PC is logged in with Admin rights and synchronising Team folders - a script simply copies the whole Dropbox folder to a separate drive.

 

However, this doesn't backup any files that the user has saved outside a Team folder, since the Admin account does not synchronise them. The 'sign in as user' functionality only appears to be available via the Admin console for one user at a time, so won't work as an automated backup.

 

I appreciate this feature is probably by design to discourage misuse, and there's already the 'backup' of the Dropbox server - but we need a local copy of ALL user files.

 

It doesn't appear there's any third-party apps or Dropbox partners that provide this functionality, but is it at least exposed via the API? i.e. if we find a freelance developer to code us something simple that can run locally...