I have to ask. Did your design include the open equipment racks & no port glass, or did you go off reservation on those?
I remember in the $20k forum Dennis said your theater & Art's were the only 2 rooms that he felt came out well despite not building them himself. So I was shocked to read that your room has audible equipment noise to the point that it bothers you and you want to redesign it. Don't take this in a bad way, but how does your theater with audible & bothersome equipment noise = success story, while my walls with a little extra flex = fail (room unsuitable for playback).
As far as MDF + absoption, I thought the back wall was generally supposed to be diffusion. So maybe use absorption on the interior of the MDF panel facing the equipment, but a diffusor on the outside facing the theater. And on behalf of Ted, I'll go ahead and recommend you use 2 layers of anything you can put green glue between for the rigid part of your panels. You might actually just want to give Ted a call and see what he thinks.
Or as an alternative, does your equipment room back up to another room? Could you put most of your equipment in the other room? Have it share the common wall between the equipment room & other room -vs- equipment room & theater. That's what I was going to do for mine, and disguise the rack sitting in the other room. If you don't have a room on the other side, then that obviously wouldn't work for you.
Hiding all those power & status lights facing the screen should help with your CR as well. But you might want to check with QSC on the minimum clearance needed in front of the amps for exhaust.