The Greenspun College of Urban Affairs’ new home at the University of Nevada Las Vegas will, by all accounts, be dazzling. Besides classrooms and offices, the 120,000-square-foot building will house state-of-the-art labs and radio and TV studios.But as students, staff and faculty members get ready to occupy the new facility, their excitement may be tempered. Like other divisions at UNLV, urban affairs is downsizing in response to funding cuts. The Greenspun College is eliminating several full-time visiting professor positions and trimming its budget for part-time instructors, who conduct many undergraduate courses. As a result, students will have fewer classes from which to choose and classes will be larger.