Luxury retailer Prada spent millions on IT for its futuristic "epicenter" store. But the flashy technology has turned into a high-priced hassle. When the Italian fashion house opened its $40 million Manhattan flagship, hotshot architect Rem Koolhaas promised a radically new shopping experience. And he kept the promise -- though not quite according to plan. Customers were soon enduring hordes of tourists, neglected technology, and the occasional thrill of getting stuck in experimental dressing rooms.