NetBeans released support Python recently. Check the features here http://www.netbeans.org/features/python/index.html

I've tried to use that IDE for editing QEngine custom scripts. Here are the steps,

1. Download and install the EA from here, http://dlc.sun.com.edgesuite.net/netbeans/6.7/python/ea2/
2. Create a new project. While creating the project, include the /QEngine home/jars folder in the Python path
3. Wait for NetBeans to scan and index the added folder
4. Now, you can use the IDE editor for editing custom script files including code completion.

Try and let me know.

Rajasankar
rajasankar at zohocorp dot com