Multiple file uploads, based on the BlueImp jQuery uploader. Makes it very easy to attach one or more files to whatever you're editing. It's also easy to present that list again on a later edit so that existing files can be managed side by side with existing attachments.
It would be nice to abstract rsync calls to a library, e.g. https://github.com/albertofem/rsync-lib, instead of using directly system() calls