I see, thanks. My comment above doesn't apply, then. However, I think you can get very nice-looking, cross-platform, native apps with python and QT, GTK or other toolkits.
Examples? I've seen okay looking GTK and QT apps running under a specific OS or distribution, but usually when you try to run them on a different OS they fall apart.
Qt supports different native styles, Qt looks - and behaves - native in Windows, OS X, GNOME, KDE, ... Try QtCreator for example, or VLC, or VirtualBox, or any other application made in Qt.