I have been exploring a neat little Java-based tool called MindTerm that can act as an ftp proxy as well as an SSH client.
While I am glued solidly to using the Terminal utility in OS X (and FTPeel for FTP tasks), I do like the MindTerm ssh client and proxy capabilities. More importantly though, it can be used an a standalone applet or as a library within another web or desktop application.
The key factor to me is its ability to act as an ftp proxy, allowing standard ftp usage from the desktop which is routed over an ssh connection. In essence one launches the applet, connects to a host, minimizes MindTerm and then launches their ftp client. Within the ftp client the host is changed to 127.0.0.1:21 and an ftp session is routed over the previously established ssh connection.
The product is open source and available for free limited commercial use for 100 users or less. Larger site implementations may incur costs. The company, AppGate Network Security, also offers some OEM licensing for those seeking large scale distributions of products with the MindTerm library embedded.