Gwizard is a set of Elisp functions to aid GTK+/Gnome/Bonobo programmers written by DirkJanBinnema.
The package contains gwizard.el, the documentation and sample code. There’s also an article about the Bonobo support online:
It shows how some elisp makes programming Bonobo components quite easy.
Note, however, that it’s for the Gnome 1.x environment.