This'd be a really big job, probably a few weeks work.

I wouldn't develop using catalogues myself, but I'd probably pull the UI for catalogue field specification into the add/edit quiz screen for question specification. The amount of data for each question would be extended and the UI would allow specifying it in an intuitive way (currently you hand type all the Q&A's as text, but that metaphor breaks down when each question has complex options associated with it).

Once the new UI was made, it would really just be a case of adding the features. But there's a lot here to add.