Nautilus mount devices as other users

[singpolyma]

I am running Ubuntu on a PC connected to my TV. I have an "onscreen" user that is actually the one running GNOME, etc, but I have all data stored under other users (one user for each person in my house). When it comes to remotely adding files this works great (SFTP drag-and-drop into their user, done), but leaves something to be desired when physically using the system. I can run nautilus --no-desktop with gksu as the different users, and it runs, but it cannot mount devices or access mounted devices. It cannot show the computer: area at all, in fact. What are good ways to fix this?