Compiled By Michael A. Verespej If trade shows are any indication, a return to more formal business attire may be in the offing. Research by Incomm International, Chicago, found that only 45% of customers responded favorably in 2000 to the casual attire of salespeople staffing trade-show exhibits. That's a dramatic change from the 86% who found such attire acceptable just two years ago. Incomm's findings parallel the recent increase in sales of high-end men's suit and sales drop-off for khakis, says Incomm President Allen Konopacki, who suggests that globalization is driving the change away from casual attire. "Most companies do business on a global basis and our research found that international companies do not always accept casual attire. As a result, American companies are being forced back into a conservative appearance." Today's in-look, he says, are dress trousers, dress shirts, leather shoes, and no coat. The tie is optional.