Giving GtkFileChooser different backend functions.

[Richard Shann <richard shann virgin net>]

Does anyone know if it would be at all easy to intercept the calls the
GtkFileChooser widget makes to get files/directories?
I am sure it would take me too long to get to grips with the whole
subclassing thing to create a special version of the widget, but if I
could just sneak in there when it was wanting the list of
files/directories I would be a happy bunny. 
Preferably some hooks in the backend but even at the cost of having to
monitor version changes... can it be done in a few lines of code?
Richard Shann