The salty shirt!  
  
NEW VERSION
UPDATE 28/08:  turned the grey scale into vectors to make it printable with 1 color:  
The final design:
  How it should look like:  

OLD VERSIONS: 
The design:    
    How it should look like (the base color has white Shishi and Orochi) 
    A new logo!  
   Where the logo?  (I prefer the first one for the position)

... or maybe the logo on the back? Something like this:
UPDATE V2 fixed some random things on the design  
  UPDATE The whole thing can be less detailed and still look nice, here is an example of a less detailed Shishi that can be replaced with the more detailed one: 
   10% discount with the promo code "
KFSALT"