i think you can do 2... but it may have said that because you might need removal of that lower psu chamber cover.
not 100% sure about it... but i cant see any other reason why it says only 1.
I like BeQuiet cases, they are fairly nice for what you pay you.. you should although also check out the Lian Li O11 series as well, as i think those are very blingy cases and fairly good ones also.