This seems like a good solution. Hacking around with a NAS is probably going to be problematic. If I were to go the NAS route I'd probably go with a Synology or

This seems like a good solution. Hacking around with a NAS is probably going to be problematic. If I were to go the NAS route I'd probably go with a Synology or something similar, which seem somewhat more hackable/scriptable. Another option, might be a normal workstation with a removable USB HD. Setup scripts to automatically backup to the USB drive and the user just unplugs it and takes it home every day.