I've been working in upstream nautilus to get this new feature, but due to the 13.04 release uncertainty, it has not been possible to merge these changes into the ubuntu package.
It basically makes nautilus to always try to focus a window or tab pointing to the requested location before opening a new window, and this is needed to fix bug #692444.
It also adds a new "--new-window" or "-w" commandline option to force the opening of a new window.
Regressions potential is very low.
The upstream bug is https://bugzilla.gnome.org/show_bug.cgi?id=694034 and all the patches have been merged on git (commits [1], [2] and [3]).
Backported patches for the ubuntu package are available at lp:~3v1n0/nautilus/reuse-already-opened-views/+merge/152981
[1] https://git.gnome.org/browse/nautilus/commit/?id=c8ee0c5
[2] https://git.gnome.org/browse/nautilus/commit/?id=d0b0b
[3] https://git.gnome.org/browse/nautilus/commit/?id=ce4255cf
Thanks Marco
I'm not part of the release team, but looking to the diff and the rational I want to give an informal +1 from the desktop side ;-)