As fine-art trials go, they don't get much juicier. Domenico De Sole, chairman of Sotheby's auction house, was suing Knoedler & Co., once one of New York City's most prestigious art dealers, for selling him a dud. In 2004, De Sole and his wife paid $8.3 million for Untitled, 1956, a work by the midcentury Abstract Expressionist Mark Rothko, which they loved right up until they discovered, seven years later, that it was really a painting of squares done by a Chinese guy in Queens.
The painting was one of dozens of fraudulent modern masterpieces the now defunct gallery sold, to the tune of $70 million, in one of the most shocking art swindles in history. The real painter, Pei-Shen Qian, has fled to China. The Long Island dealer who…