Any computer which can advertise vnc over mDNS (which apple calls 'Rendezvous') will show up in finder sidebar. I have my own custom a raspberryPi image set up

Any computer which can advertise vnc over mDNS (which apple calls 'Rendezvous') will show up in finder sidebar. I have my own custom a raspberryPi image set up to do this out of the box. You can get this going on any Linux box by installing avahi. Then google for instructions to configure avahi to advertise vnc. I believe if you advertise smb or afp that will also cause it to show in the sidebar, but I haven't tried it.