Rising from a 60-acre field of old cypress swamp and cattle pasture near the Orlando airport, the 7-story Nemours Children's Hospital will be a monument to "best-in-class" care, its leaders boast. That may be the case. But at a cost of about $400 million, the equivalent of $4.2-million for each of its 95 beds, Nemours will also rank among the more expensive children's hospitals ever built when it is completed next year. Some people believe construction never should have begun. Florida health planners twice rejected Nemours' applications for a new hospital, noting that Orlando already had two children's hospitals; most cities have only one. A third hospital could duplicate existing services, driving up costs for insurers, employers and policyholders.