There are server power supplies than rate at 1000watts. Look around. They're a bear to find but worth the hunt.
And Jac the monitors don't pull power from the computer. Neither do the speakers. The keyboard even if usb pull whispers of power. And why have 2 optical drives? Any dual layer drive worth being my systems will read anything you toss in them. Unnessacery power drain having 2.
What's killing the juice in that configuration is the 2 dual core cpu chips. Then add all the cooling fans for the heat and dude you better get a server tower with lots of elbow room and the 1k psu. The vid cards can get a bit demanding however.
What I did in my systen is use 2 psu but devided the load of the over all system between them. The motherboard is driven off one psu while the optical and hard drives are ran off the other. Oh and the cooling fans run off the second psu. Works fabiously. It's all happy and runs great.
That isnt actually his computer guys, thats just a dream computer... I think
But yes you can use two powersupplys. A lot of pepole will have a cheap like 250w or 300w just for lights fans and what not. Then they will have a nice, bigger powersupply for the rest of their computer.