Sub-Account Backups

I'd like to have some way to back up an individual sub-account (or group of individual sub-accounts) from within Webmin. Ideally, I should be able to specify what to backup, i.e., the entire sub-account, email for the sub-account, or specified directories within the sub-account. The backup should be capable of automatically assuming whatever privileges are necessary to create a gzipped/bzipped tarball of the targets, and then email a link to the tarball for easy downloading to a remote server.