Making a custom hanging rack is not difficult, but I think with that weight requirement whatever you get is going to need to be mounted to two of your existing wall studs, via lag bolts.
A custom rack of 3/4" cabinet grade Baltic Birch comes to mind, because you can cut out rectangular holes on the side panels, between the shelves, to lighten the look, without compromising structure. Veneer the pieces with Walnut veneer (to match your Core Audio racks), but leave the plywood edges raw (sanded, rounded and stained to match the walnut, but with that cool, modern look of the layered plywood veneer cores).
If I were more proficient at drawing on the computer, I could get the design idea across better.