The fashion world is having another fling with Scottish tartan, presently seen as sneakers or a vintage tam-o-shanter. The couple above, seen in Paris last month, were slipcovered in tartan, including their luggage. The man at right is wearing a trompe l'oeil kilt that was actually a bath towel bought at a Woolworth's in Edinburgh. He was at a Scottish dance at the Cathedral of St. John the Divine in New York last week, where many of the guests, bottom row, were wearing tartan clothes. The same week, there was a party for the book Tartan: Romancing the Plaid at Saks Fifth Avenue with the authors, left, Doria de La Chapelle, seated, and Jeffrey Banks.