TBH, no 1200W PSU can be called "cool temps" and "low noise".
That's because of 2 reasons:
1. You would need 4GPUs with latest i7 (or AMD alternatives) which themselves would be noisy (the case itself would matter very much)
2. A 1200W PSU is too inefficient at low loads (300W-400W that 1x i7 with 1x high-end GPU would consume), which means it will have a higher heat output compared to a 600W PSU at the same load.
The reason that I am such a critic is because if you really need such a PSU, you would have already looked at many reviews of GPU/CPU (where the real load and noise is tested), while if you don't need it, you would be spending money just for numbers.
So if you don't do multiGPU/multiCPU, look instead for a half power, reputable manufacturer PSU (most would agree of Antec, Enermax, Seasonic, Thermaltake, Corsair, Zalman)
PS: www.silentpcreview has a table with recomended silent PSUs. It's last category is 650+W, where a Zalman 1000W is the biggest.
I am actually in the process of my first build and am, in fact, considering multiple GPUs. But, I may not be able to get them all at once. So, the reason for the question is to have a PSU that is capable of handling 2 or 3 GPUs in the near future (3 months or so).
Are you saying that it would be harmful to have a 1k or 1.2k PSU in a system with a single GPU? Or is it just a matter of efficiency that you are pointing out?