Here is my idea for your a/v niche, incorporating stainless steel, brushed nickel, and cherry. The lower section is media drawers separated by a inside curve of stainless (echoed in the toekick). The upper section uses your existing lights to illuminate a stainless wrap featuring an off-center cherry oval column upon which 3/4in adjustable glass shelves hover, supported by satin nickel hardware (not rendered). These shelves are rated at 120lbs per, so they will easily hold even the heaviest amps. All the wiring will be fed down a chase that runs down the center of the column.
My only reservation is the stainless-heavy top section. I suspect it will tie in nicely with the stainless fireplace--but my guess is that you have a clearer conception of the finished room, and this detail would benefit greatly with your input. Let me know what you think.