And here my past comes back to haunt............
Its really more common in the U.S. than most would think
,
but not in restaurants.
Back in the 1990s this was a growing trend as a "party feature" in the more exclusive "kinky" lifestyle. Not always for sushi, but for serving many types of appetizers and party noshes. Just when the guests were known to prefer sushi over any other cuisine and could afford the catering, it was this presentation. The "serving platter" was always a volunteer, so the price was not bankrupting anyone.
So my guess is it is definitely American in orign.