Want to let your customers know how committed you are to serving them? For the past four years J. W. Kisling, CEO of Multiplex Inc., a St. Louis maker of beverage-dispensing equipment for the food-service industry, has listed the home phone numbers of the company's 16 directors and officers in its catalog. Next to the list is a suggestion to call in case of emergency -- if satisfaction can't be had from an area manager. "The secret," Kisling confides, "is we only get a couple of calls a year. But seeing it in writing impresses the hell out of our customers."