Not Amish, exactly, but there are mennonite communities that are "modernised". My home town was one such area. Half of the population is German mennonites from Mexico, who over the past several decades have returned to certain areas of Canada. They dress very conservatively, like the 1800s, the girls wear long flowery dresses, the men are always in formal button shirts.
They use all the conveniences of modern life, cars, electricity. They live in town with everyone else, but they don't really assimilate well with the rest of the community, and there's a lot of prejudice against them because of this. ie. they don't speak english well, many of the parents don't send their kids to school, and force them to help them work on the farms where they work as seasonal work.
These swimsuits seem designed perfectly for them, in fact.