From the gourmet sandwiches served on hand-painted ceramic plates and sparkling water poured into hand-blown glasses, to the soft, modular duvet seats and martini tables with a center tube to hold a taper candle or single flower stem, it’s clear that a visit to the William White Emporium is not just another apparel industry market appointment. Yes, there are a few racks of clothes, but the store on New York’s Canal Street — and its studio across the street — serve to truly immerse visitors in the world of Will Cooper and his lifestyle brand, William White. Cooper has had an entrepreneurial bent since he was a child. He started his first business when he was 10 — Party Players Production — serving as a DJ and working weddings, bar mitzvahs and school dances. But he was always obsessed with retail and started working at Neiman Marcus in Dallas before moving on to the Ralph Lauren Rugby store.…