Sorry... wasn't trying to be obtuse. OO is from ... Moodle (abbreviation for Modular Object-Oriented Dynamic Learning Environment) ... I was just trying to play along. And, actually my little example isn't really object orientated, by definition. And, yes. The "Two courses, one content" (and other abstractions) are missing from Moodle. Adding them will be a change deep in the bowels of Moodle.... which isn't my call.
Gotta say, I'm really impressed with Moodle and Mr. Dougiamas' efforts. I'm hoping that the-power-that-be at the client company were I'm currently consulting gives Moodle due consideration. Anyway, thanks for your suggestions.
Cheers.