Temporary root-access in Nautilus?
 

Is there some way to gain temporary root-access while in Nautilus, so that specific tasks that need root log-in can be performed, such as changing permissions of files? (under Ubuntu)

Nautilus scripts are your answer. Create a file "Open as Administrator" with the following 3 lines.

for uri in $NAUTILUS_SCRIPT_SELECTED_URIS; do
gksudo "gnome-open $uri" &
done

Place the file in folder ~/.gnome2/nautilus-scripts

Open Naultilus and right click on a file or directory hover "Scripts" and select "Open as Administrator". The item will be opened as root. You can also place any bash script in that folder as well. I have one that opens a terminal with the directory set to that of the file right clicked.

just typing $sudo nautilus - in a terminal window should work on the fly as well :)

Alt-F2