Lloyd: here is the model: http://sketchup.google.com/3dwarehouse/details?mid=14dd943b8df80452af7c14c30c36d523
As for the frame: I use the outline of the opening's back face to use the Follow me tool on. It would be easier with the TubeAlongPath plugin but I need to ask TIG for some minor modifications for that plugin (the orientation of faces that are extruded).
As for the see-through window: I kep that face in the opening component till the end as it is a useful thing to qickly select all the surrounding edges (or everything with just that face) when doing the follow me operation or scaling.
Then just double click on it, make a group, cut it (Ctrl+X), exit the opening component and paste in place (Edit menu) then move it slightly back so that it's in the middle of the framing.
This way you end up with a single glass plane exactly in the middle.
And yes, that part at the end might be a bit rashly put together - I may amend it with a couple of lines of text (maybe additional screenshots, too), sorry.
(I already have the next tut with some sort of mullions just need to create the steps and upload them) 

Kris: thanks 