Good to open that tracker issue Dominique, looks like the type of thing that the Moodle Users Association could get involved with. I figure it is something that would be done mainly in Javascript and would not be wildly complex. If I could clone myself I would get on with building a proof of concept ......
It is amazing how real world use of Moodle comes up with ideas that developers like myself would never think of. I had a suggestion by Elton LaClare of Sojo University Japan for one of my own question types I think is just awesome and I know I would never have thought of it.