OUTSIDE HONG KONG'S HISTORIC Peninsula Hotel one recent weekday afternoon, two men compare their Bentleys. A gun-metal gray edition with the license plate "Iron Man" looks positively understated next to a fiery-red model whose gold paint flecks and hood ornament coated in 100 carats of diamonds sparkle in the sun.

That vehicle, worth around US $1 million, is part of a nine-car luxury fleet that belongs to Stephen Hung, one of Hong Kong's most ostentatious dealmakers.

Hung, dressed in black pants and a T-shirt emblazoned with bright flowers and geometric shapes —both very tight and very Versace—is there to do some shopping. In a private room in the hotel's Graff Diamonds store, Hung tells Arnaud Bastien, the British jeweler's Asia president and chief executive, that he has recently been to Venice, where he sailed on founder Laurence Graff's 150-foot yacht. Bastien acknowledges that his boss "knows how to enjoy" life. "Except right next to it was a 250-footer!" Hung interjects. He pulls up some photos of the trip on his iPhone and passes it around the room.

"When we work with Stephen he's always eager to have something special," says Bastien, as he produces one of the designs Graff has prepared for Hung. It is a watch face adorned with diamonds in the shape of Hung's own visage. A line of rubies is planned to represent Hung's signature look: a swath of bright red hair sweeping across his forehead. "We came up with this and he asked, 'Can you make my hair more red?'" explains Bastien.

Hung lights a Dunhill cigarette with a gold lighter. "Not many men get to try these on," he says, as he slips on a flawless 23-carat diamond ring that out-sparkles even his bright green Christian Louboutin loafers covered in gold spikes. "These are all worth over $10 million…obviously," he says, pointing to the jewels on display.