I would love to have a way to assemble a case made out of several cases, so it really resembles the real-world situation.
For now I've simply created a huge case, but in real life, my case is made of a 3x3U 168hp + 2x1U 168hp base and then two 4x3U 84hp suitcases on top. Would be great if you could add multiple cases to one view, and drag them to a more or less real-life position.
(Also, with this, I'd solve my "wishlist" problem. For now I simply use the bottom rows of the huge case as a sort of wishlist, dragging the stuff to the top that's more on top of my wishlist and gradually dragging stuff down that's not entirely off my wishlist, bus has lower priority. With this, I could simply add a wishlist-case, or, as someone suggest, a case containing modules that are not in your real case anymore.)