If you want even larger systems, you should check out the European XFEL, which was just opened, and is now the most powerful free electron laser in existence. http://www.xfel.eu/
As a die hard LCLS supporter, I have to say: XFEL has the more powerful electron beam, but LCLS is still in the lead in terms of X-rays right now (if pulse intensity/peak power is the measure).
XFEL is really an amazing machine, though, and once it is fully commissioned, it will take the X-ray crown as well.
XFEL is really an amazing machine, though, and once it is fully commissioned, it will take the X-ray crown as well.