Kefir is a code generator that writes wrapper code around Glade files. Kefir takes glade files and writes a wrapper object for each window in Python, with methods corresponding to the given callbacks entered in glade. While it won't create a sane application model for you, it will make it very simple to use glade to write the event based GUI.
It is also very flexible, at the cost of verbosity, so the developer can make any changes to the Glade file, and these changes can be imported into the python code, without losing the old code.
It can also accept any custom widget available, and there are future plans of being able to create more custom widgets using Kefir and Python.