I have looked around for these for some time... the limits imposed by the web server and/or the dynamic programming environment (e.g. PHP) are far too restrictive for the application I'm working on. We need to be able to move large graphics and video files to and from clients (ranging from tens of MB to a few GB in a single file). Plain FTP with a proper desktop client will do the trick, and we're hosting this in Amazon EC2 with EBS. User management will be done from the office via webmin. Users are chroot-jailed into their home dir by proftpd.
net2ftp will work for many clients, but we often need to move single files that approach 1GB or exceed 2-3GB which is way out of the range of any http-based uploader.
So we turn to Java or Flash - can they do it? From within the web browser establish an FTP connection and grab a huge file? There are licensed applets and such out there, but none seem convincing.
Again, I'm looking for some code that can speak FTP and read (& write?) the local disk, that is delivered in a web browser, and can move single files of 2GB+. The reason for having a web-based interface to FTP is to skip the software installation step for our clients. I will consider proper desktop client software as long as it's "portable" and at least Win+Mac and can be easily configured by lay-man users in a hurry.