Power conditioning for multiple dedicated circuits

Well, a little late now, but you would have been better off running 220V lines and putting a transformer in the room. You would have lower voltage drop from the length of the cables, and better noise isolation thanks to the transformer.

If you must go this route, I recommend Furman strips or conditioners with LiFT and SMP, or Tripp Lite Isobar Ultra as affordable ways to reduce noise.

Eric, I always had an interest in doing just what you recommend here. In fact, I believe that the Richard gray Company used to make what was called the 'Power Station'. You give it 220AC, it uses a step down transformer, and produces 120AC balanced power IIRC. Of course it was massive and too expensive for me, but it did catch my eye.
 Long ago, I was able to run 2 separate 120 lines out of phase with each other, using some equipment on one line and other equipment on the other. That is why this thread appealed to me with the ganged breaker doing the same thing. Can't say whether or not it is an actual benefit to it, but want to believe that there some out of the box possibilities to be groomed from it.

I have been thinking more about my 12/3 wire configured for two separate circuits.  There is a single neutral and ground wire going back to the panel.  

Does this matter when all neutral and ground wires in a house are going back to their same respective bus bar?  The neutral and ground bus bars are even connected within the panel.  

I would like to understand how two of each returning the panel compare to a single run.

Richard Gray's power stations were resonant filter tanks, widely available for 110 VAC but I'm sure they made at least 1 version that was 220 to 110.

I believe Equitech makes a number of suitable models today.

There are a lot of companies that offer multiple types and sizes of conditioners from single to 16 outlets on a single conditioner, but i would look at audio magic for a whole system conditioner for at least your front end components because it will way outperform the monster power.