I love the design of headphone cases like 
 
LCD-3

B&O

Sennheiser HD800

Sennheiser Momentum

for headphones 
 
and cases like

(Monster Gratitude)
 
for in ear headphones.
 
I'm buying a HD 598 headphone and  and found out the headphone doesn't come with a carrying case... how depressing  
I also am buying torque t103z in ear headphones and I would love to store it in wallet-like cases like the case for monster gratitude ( as seen above)
 
if you guys know of any cases like these (cases sold separately), please let me know!

Slappa makes some decent headphone cases:
http://www.slappa.com/HardBody-PRO-Headphone-Case-Dimple
http://www.slappa.com/HardBody-PRO-Full-Size-Headphone-case

Brainwavz makes a good case:
http://www.amazon.com/Brainwavz-Large-Hard-Headphone-Case/dp/B00HPPI0W8/

I have no idea if/which of these cases fit the HD598.