It would be nice to create a UNIX socket between both UNIX environments. This could improve performance for things like X sessions which currently have a tcp/ip/eth overhead. I've experimented with using a serial socket device. I found out the named sockets are created in /Library/Parallels/Parallels Service.app/Contents/PlugIns/Parallels VM.app/Contents/MacOS then used socat to communicate over it. It works fine for ascii, but I have yet to establish an X session over it (I've tried raw and -g modes in socat to no avail).
