By Melissa Ludwig AMERICAN-STATESMAN STAFF Sunday, April 4, 2004 Evelyn Volz is obsessed with the idea of Spam. Not the actual food product. The 17-year-old senior at St. Stephen's Episcopal School dressed as a can of Spam for Halloween in the ninth grade, owns a Spam T-shirt and calls her mother "Spam." But before she accepted a plastic cup of green eggs and Spam at Saturday's Spamarama, she had never even tried it. "I was always too afraid," she said. Volz claims her affection for the pork product is tied more to its status as an icon of the post-World...