Well, yes, you could try to do something by linking different quizzes through the Overall feedback. In fact, Rita Tingle, an OU academic tried it as a research project. Unfortunately, she found that the resulting UI was just too clunky, to such an extent that it got in the way of student's learning.
So, this really does require a new acitvity module, and we have another thread going on about that now: https://moodle.org/mod/forum/discuss.php?d=215627.
Just to note that there is MDL-36280 about this.
To really do what you are asking for would really require a new Moodle activity type. The way Moodle is designed, with a question bank that could, in principle, be used by any activity, not just the quiz, should make it relatively easy to implement such an activity, but it would still be a substantial project to create such a thing. Anyone who is insterested in such a thing would probably find this documentation helpful: http://docs.moodle.org/dev/Using_the_question_engine_from_module.
There is a related, but slightly different, sort of acitvity which I wrote about here: http://tjhunt.blogspot.co.uk/2011/09/what-i-want-to-build-next.html
Ah! I have seen that happen before, and I don't entirely understand it. Somehow, git decides to add a submodule, rather that the files.
What you need to do instead is replace
git add .
by
git add question/type/pmatch/*
We are interested in this at the OU, but I can't remember what the current state of play is, and the person who would know is away at the moment.
I think we fould that we could get some of what we wanted using the pmatch question type, doing more is somewhere on our todo list, but I can't remember where.
Hmm. This is an almost entirely useless reply, isn't it. Hopefully I can remember what is going on, and then post more.