How far would you go for good fruit? Alan Smith, the owner of Tropical Fruit Trees, a Florida nursery that specializes in rare and exotic plants, has been receiving orders for fig and grapefruit trees from a sheik in Dubai. Another buyer, in Siberia, sent Smith a $20 bill from the black market for lychee and longan seeds. Currently Smith's top seller is the kaffir-lime tree, plus, he reports, "the Germans are going crazy for curry-leaf plants." Born in Zimbabwe, Smith got his start working on a mango farm in South Africa. He moved to Florida in 1982 and found a job at a nursery, where he was intrigued by repeated inquiries for kaffir lime and other exotic trees. Smith grafted cuttings obtained from wholesalers and propagated a collection in his backyard. He now has about 10,000 trees, including blood orange, papaw, limequat, macadamia and cherimoya. Smith has clearly found his calling; should there be a freeze in Florida, he says, "I don't care, I'll start all over again" (727-686-3110;