A friend gave me the tip to connect a virtualized Windows XP machine. All Mac programs can access the Internet and programs like the Putty SSH client running inside the virtual Windows XP guest OS can access the remote system. This solution is slightly more convenient than two separate machines because it already allows copy/paste and drag/drop. However, I really wanted direct SFTP and SSH connectivity from my Mac client programs like Terminal and Interarchy/BBEdit. The solution is SSH tunneling through the VM, and Putty can do this, but I wanted a bit more flexibility and automation of the process by using Linux instead of Windows inside the VM (and I actually could not get the VPN connection running in my virtual Windows Vista, even after disabling Vista’s UAC got me one step closer). What follows is the description of my setup.
This is a fairly rudimentary version of Hamachi for OS X. It is a console package (no pretty GUI), it requires manual installation and depends on tunneling drivers by Mattias Nissler. See the README file for details.