Description of problem: See http://thread.gmane.org/gmane.linux.redhat.fedora.devel/76670 Apparently many people didn't even know about beautiful mechanism of locales, which is available in Linux. Theory is that if there is nice GUI configuration mechanism for that, locales might be more used. KDE has pretty good tool for this, but certainly some GNOME "don't stand in the way of users doing what they want by forcing them operate your program" could be useful. I know that there is an option to change language of Gnome session as whole (which sets LANG variable), but AFAIK it is not possible to change individual LC_* variables.
Feature requests like this really need to handled upstream. FWIW, the control center contains a localization capplet, but it doesn't do anything right now, therefore it isn't built. Any solution you come up with here will have the suckiness factor of 'requires relogin'.
Done. http://bugzilla.gnome.org/show_bug.cgi?id=516756