Broadway Blues

David Letterman's decision to stay in New York means the Ed Sullivan Theater building on Broadway gets a face-lift. But there's bad news: CBS may evict many of the building's current tenants — businesses such as vocal coaches and lighting firms — to make room for Dave. ''People here are worried they'll be put out on the street,'' says one tenant. The network admits some occupants will be displaced. ''We need a couple of floors of office space,'' says CBS senior vice president Ed Grebow, ''and some tenants will be asked to leave.''