I have never done anything quite like that, and I do not recall anyone on the forum discussing it.
If I was going to do it, I would build a new panel in the right hand pane, rather than trying to use the inventory, using JavaScript/JQuery. It will not be easy! I guess the first thing I would do is look for a JQuery library with a collapsing hierarchy. How you would relate that to your Quest data..?
Not sure if it will help, but here is the interface library from
Deeper, which might gives you some clues.