Funny, it reminded me of the Corsair Spec line up a lot so I went to compare them. Don't know who the OEM is but it's definitely the same!
The single front LED intake fan, the two 5.25"drive bays, the off-set top fan/radiator mounts, the side panel bulges and window. Even the front I/O is the same with the audio ports in the middle with the USB ports on both sides and the power button on the left.
Even the casefeet are the same.
Not to mention the internals
Edit; Well I just noticed the top image of the Spec 02 is actually a spec 01. The Spec 02 has a slightly different shaped window (with one corner 'cut off'). The Spec 02 and PS11 also have the same PCI brackets.
The only things that are different is the front panel bezel, the Corsair coming with a rear fan where the PS11 doesn't, and the PS11 having 2 USB3 ports while the Spec 01 and 02 both only have one.
I was thinking of the Cooler Master CM 690 II but I was wrong now looking at the spec 02, I knew i'd seen the layout before but I got the cases mixed up.