You may want to look at simply using gedit. It's not a python-IDE per se, but it's very fast and fun to use as gnome's official text editor.
Maybe I'm crazy. I think I'm not the only one doing light coding using gedit, though. There are some interesting plugins to aid python coding too: http://live.gnome.org/Gedit/Plugins ; Among them, I have the Pylint and PythonOutline plugins installed.
Good luck hacking on PiTiVi!