What are the equivalents of "gksu nautilus" in other Ubuntu Derivatives

Xubuntu

For your case you have the Thunar file manager in which case you would use:

gksu thunar or gksudo thunar

If you had Kubuntu then the File manager would be Dolphin in which case you would use:

kdesu dolphin or kdesudo dolphin

If you had Ubuntu you would use Nautilus as the File Manager and then would use:

gksu nautilus or gksudo nautilus.

If you had Lubuntu you would use PCManFM as the File Manager and then would use:

gksu pcmanfm or gksudo pcmanfm.

The default file manager in xubuntu is Thunar.

gksu thunar