… accessed from Python.

Creating a new function gimp_value_array_get_color_array(). This should normally
not be needed (it isn't in C), but because of GObject Introspection limitation
and the fact that pygobject will automatically try to convert GValue to the
embedded value, we get this weird situation where the result is unusable in
Python for certain types. One of these types is GimpColorArray.

I suggest an annotation request to GObject Introspection:
GNOME/gobject-introspection#492

I think that with such annotation, followed as a second step by pygobject
support, correctly handling NULL terminated C arrays generically should be
feasible by bindings.