building a modular interface

[Lachlan <lachlan 00 gmail com>]

hi,
I've decided to hunker down and start developing my first gtk
application. I have a few questions that google hasn't really been
helpful with. I know how to create and load an interface built from
glade but is it possible to take a more modular approach?

For example I would like to be able to load an empty window, check
config file that defines how the interface looks and import the
widgets into that empty window.

so a default config file would be something like this in yaml:

--- FooBar
vbox: 3
    hbox: 2
        item: menu
        item: progress
    hbox: 2
        vbox: 2
            item: filelist
            item: fileinfo
        item: preview
    item: statusbar

What I would then like to do; is be able to load or not load parts in
any way the user feels like using this config file. That way it can be
arranged easily without having to edit the entire interface. My guess
is that there would be a main ui file that has the basic window and
then each "item" is loaded from it's own config file which i think can
be done with glade's "Add widget as top level".

I'm looking to do this all in pygobject and using xml/yaml/whatever.
Is this kind of stuff possible or am i barking up the wrong tree?