... and following my previous two automation-related posts, the issue I'm most immediately interested in is whether the scripting API can access the Graphic Objects, and if so, by what path?

Thanks,

Graham

Yes it can.  There is an example of this under Downloads/Other Files/Scripts:

http://www.modelright.com/files/folders/scripts/entry344.aspx

The path is Model Subset/Diagram/Table Graphics.  You can use the Tools/Meta Model Browser to figure this sort of thing out (though it still might have  been hard to find).