Xigmatek's new NRP-HC1201 is a solid 1200W power supply with a large number of features. The modularity concept works well and will make your life easier during installation. Even though the unit is bigger than the standard ATX form factor, it should fit all cases. If you need that much power you will usually have a big case anyway.
1200W of power may sound like a lot, and it is. So before just shopping for big numbers (and spending big numbers) make sure you really know what kind of power draw to expect from your system. This will also save you quite some money, because you don't pay for power delivery capability that you will never use. The fan noise of our sample was high, but as Xigmatek has told us, the loud fan speeds will be fixed in the revision that goes on store shelves, so this is not really an issue.