Hmmmm, I am very skeptical whether that stick & platform monitor mounting set-up will hold out. What will it be made of? Metal? Acrylic? If they happen to break, then that's a monitory out of the windows straight away.
I missed something before, but this was addressed by someone else but the way your air flow is heading, your graphics card considering that you have placed a 'gtx 680' in your plans are worrying me. It's basically a wall, there's a reason why in normal cases the air flow goes from the right edge of the motherboard to the I/O panel on the left edge of the motherboard. Motherboards are also designed to take advatage of airflow this way, where conventionally a fan will blow over the southbridge heatsink or whatever heatsink is down there.;
In my opinion, you should have the airflow coming from right to left (when you're sitting down facing the front of the desk). This way your airflow will be less congested.
I know this has been addressed before, but I am giving another warning.