After discussing scim with Warren, we want the "Input Methods" submenu to be hidden, since input method switching should be done with the scim notification area icon. Might be worth hiding the "Control Character" menu at the same time. I'll attach for gtk which adds to settings for this, and exposes them as xsettings. Still to do: patch gnome-settings-manager to wire them to gconf keys, and add the gconf keys to a suitable schema.
Created attachment 120170 [details] gtk patch
Created attachment 120171 [details] control-center patch
Created attachment 120172 [details] libgnome patch
Should be in rawhide tomorrow