Hi all. I'm designing and building my own wood computer case in which I plan to have two 2x120 radiators positioned side by side, with a 2 or 3 inch gap between them. A fan will push air from outside the case into one radiator, the air flows into the sealed space between them, and then is pulled out through the second radiator and exhausted outside the case. 
 
With humble apologies for an ASCII illustration of this, rather than some CAD rendering, it will look thus:
 
              -> | fan|rad  ->  rad|fan | ->
 
This will therefor be a push/pull configuration where the air is flowing through two radiators rather than just one. I acknowledge that the air coming out of the first radiator will be somewhat warmed, and therefore will cool the second radiator less than it cooled the first, but I believe that with sufficient airflow through them both the overall performance will still be quite good.
 
I considered using a single 4x120 radiator instead of this doubled-up 2x120 configuration, but the 2x2x120 configuration will allow the computer case to be more compact, which is one of my priorities.
 
Question: has anyone used a setup like this before? How was the cooling performance compared with a single 2x120, or compared to a single 4x120?
 
More on the planned build: My machine currently has one 6-core Xeon 5680 and one EVGA 1080 SC. I plan to upgrade the cpu to a new 6-core i7 6850 in the near future, and leave the door open to adding a second 1080 SC in SLI. I plan to have water blocks on the cpu, the gpu, and the motherboard chipset. I have lately been overclocking the cpu and gpu, but only moderately. I refuse to add voltage and drive up power consumption very much, so this will not likely ever be pushed to very aggressive overclocks.
 
The configuration I envision will dump the heat from the most heat-producing components of the machine directly to the outside of the case without it ever entering the space where the motherboard is, so I believe that moderate case airflow (1x140mm intake, 1x140mm exhaust) will be sufficient to keep the main interior of the case near ambient. The power supply will be positioned at the bottom of the case where it will draw fresh air in through a port in the bottom of the case and exhaust it out the back of the case, likewise not exposing the main case interior to hot air.
 
 
I'm definitely interested in anyone's comments or experience regarding this setup.

Way to much to consider here to make answering your question a qualified answer. Use paint and give us a general lay out of things like top, side, & front view followed by a list of components then I could give you a bit more than general idea. For example is the 1080SC have blower fan? Is the orientation of the rads front to back side to side? etc. If you are building it yourself then I'd consider a layout that doesn't dump hot air into the other Rad? Fin count of the rads or model would also be helpful. Get the drift?
 

 
 

I ran a stacked setup for a while on my build. And while it performed just fine, I decided to change it this last go around with loop maintenance. I removed the stack and placed 1 of the 2 rads outside the case off of the back. And with all the same components I dropped about 3 or 4 degrees on my GPU's while folding. Here is my thread when I posed this question so you can see the answers http://forums.evga.com/m/tm.aspx?m=1835855

Hope this helps.

^^ More good info for you
 
Now I did have a thought.  Since you are building this from scratch, I would consider doing it this way instead.
 
As I do not have a diagram written as this was a random brain storm, here is my thought.  Your current setup, for descriptions sake, will be a sealed chamber flowing air east to west, in through the eat rad through the chamber and out through the western rad.
Now this will function similar, but need one extra hole.  I would make a spot on the north wall, for 4 120mm fans as the input, and have bot the east and west rad being exhausts.  You get the dual rad benefit, but without the issue of recycled warm air.
 
Of course this is subjected to several factors like logistically will it fit, and how wide is the chamber etc, but I think this is a possible fix that gives you all the advantages you were wanting and none of the potential challenges.

For anyone interested in the actual construction concept for this wood case, I've done some experimentation already to test out the idea I had for the physical case construction, and it's looking really good so far. I wanted to bend, flex, and otherwise try out whether the construction I had in mind would be sufficiently strong, and it appears to be just fine.
 
The primary "skin" of the case will be 1/4" baltic birch plywood. This skin will be attached to a framework made from narrow strips of 3/8" baltic birch plywood. The strips will have rabbets cut onto their edge so they can be joined with a simple overlap. One of the pics below shows this. I use a miter saw to cut 45 degree angles onto the ends of each "beam" in such a way that three of these beam ends can fit together to make a corner for the case. The 1/4" baltic birch skin is glued onto this, cleaned up at the joints with a router, and then the edges rounded over with a 1/2" radius roundover bit.

The case will have removable side panels made from the 1/4" ply that will overlap slightly onto the 3/8" edge beams and be fastened with screws. Any holes or ports cut into case will have their edges rounded over using a 1/4" roundover bit.

I'm planning on covering this red tolex, and using corner-strengthening metal caps. It will look very similar to an electric guitar amp cabinet I made before.


 

Quick shot of the electric guitar amp cabinet whose look I am duplicating for this computer case, with obvious adjustments for functionality. It shows a removable panel held on by screws, the black metal corner reinforcement hardware, the rounded edges, the red tolex covering, etc. I will also have carrying handles built into the side, but they'll be smaller and go in less deep into the sides of the case than the ones I used for this amp.