As for GTK apps under Gnome environment it's possible to set all applications to use Emacs-like input scheme:
$ gconftool --set -t string /desktop/gnome/interface/gtk_key_theme Emacs
$ gconftool --get /desktop/gnome/interface/gtk_key_theme
Emacs
I wonder if it's possible to adjust input for all QT apps in a similar way.