Here's the tip of your lifetime sushi lovers...
Every Japanese-trained sushi chef (far from all of them are) has a "signature" sushi that is his/her own invention...and they guard it very, very closely.
Your assignment is to befriend your local sushi chef, compliment them, encourage them and generally suck-up and kiss their a**, then pop the question. "Do you make a sushi that nobody else does?"
You will be surprised, amazed and astounded.