GadgetFreak makes some good points. I agree that there are a wealth of alternatives that would be very pleasing.

That said, if the host is doing a course menu as would occur in Japan, and one of those courses is sushi, it may be necessary to come up with an alternative so as not to make the guest terribly uncomfortable at that stage of the meal.

A thought that occurs to me is that the inside part of a loaf of french bread (i.e. the soft part after the crust has been removed could be shaped to roughly equate to a piece of rolled sushi rice) could be used. Then one could place a piece of similarly colored meat (roast beef for maguro for example) on the bread and place it on the plate discretely.

Mike