i found this on the internet
and its free for non-commercial use
maybe it can be intergrated into hfs, or if the developer wont allow it, maybe you can provide instructions about how a user can intergrate it into hfs himself
some info about it
JUpload is an easy to use java applet for uploading multiple files to the webserver using the post method of html forms as described in RFC 1867. It is more comfortable and easier to use than most browser's internal file selection dialog. The user can manage his upload queue and has a status monitor showing the percentage increase of the upload and the current file transfer rate in kilobytes per second (kb/s). Features include image preview, file size checking,
aborted upload resuming, secure transfer and much more!
website:
http://jupload.biz/