An item highlighter hotkey would be pretty swag too
Though it is the kind of mod that I don't mind leaving on. The wall and roof hotkeys are fantastic as I hate not having walls, but there certainly are times when it makes things a lot easier.
But really this talk just raises the question that comes to my mind quite frequently; why is stuff that can't be found elsewhere in game just lying on the floor of caves, and only caves? This was the question that spurred me to make this post originally, as the answer to the question is; it doesn't need to make sense, it's a balancing mechanic.
At least with different "cave-type" locations (sewers, bunkers etc) that balance can still be maintained while adding a reasonable level of depth to the system.
It would also open up the areas available for "caving" instead of limiting it to just mountainsides.