Designer Tom Mark's bodacious dresses help celebrities show off their bodies of work. His dresses hug a curve as confidently as a $150,000 Ferrari. His client list includes Drew Barrymore, Courteney Cox, Baywatch's Yasmine Bleeth -- and half of the rest of young Hollywood. Yet, if Tom Mark feels he's got the fashion game beat, the designer has a funny way of showing it. Working late nights at his Los Angeles factory, Mark can spend hours fine-tuning the armhole of an evening coat. Often he'll painstakingly hand-stitch 30 version s of a dress -- until he sense he will hang right on Tori Spelling or Alicia Silverstone.