As quickly as they rose, metrosexuals are disappearing, writes John Huxley.Barely two years after he was discovered - alive and well and living it up in Sydney - metrosexual man may be facing extinction. That, or he is just moving on as confused males everywhere seek new ways of expressing their masculinity, their essential "M-ness". So says an international trendspotter, Marian Salzman, the sassy, savvy New Yorker credited with identifying straight, urban males suddenly doing "decidedly gay" things: taking an interest in fashion, fragrances and skin-care products. Think footballer David Beckham, Australian swimmer Ian Thorpe, or even former US president...