Rumor has it the Chicago Symphony Orchestra requested something short and sweet from the three University of Chicago composers it commissioned to write new works for the centennials of both institutions. Iconoclast Ralph Shapey, characteristically, turned in a monumental score for a full orchestra. The hour-long, four-movement Concerto fantastique--dedicated in part to Paul Fromm, the wine merchant, philanthropist, and unstinting patron of new music who played an important role in bringing Shapey to Chicago 27 years ago--is meant to showcase the CSO's first-chair musicians. Parts of its were composed in the contemplative, quasi-religious vein of Beethoven's last quartets, and since Shapey has recently been so keen on the rhythmic vitality of percussion instruments, they'll probably figure prominently. Daniel Barenboim was scheduled to conduct these performances, but because a last-minute ear infection has stranded him in Paris, Shapey will take his place--probably for the best considering Barenboim isn't exactly empathetic to certain kinds of contemporary music and his conducting probably wouldn't have met Shapey's approval. The top half of the bill is Liszt's Piano Concerto no. 2, played by pianist Alfred Brendel and conducted by Shanghai-born newcomer Tsung Yeh. Today, 1:30 PM, and Saturday, 8 PM, Orchestra Hall, 220 S. Michigan; 435-6666.