Some of those models I have made myself on paintbrush. Check them out:
Home Insurance Building, Chicago:
AT&T Long Lines Building, New York City:
United Nations Plaza Building, New York City:
New York Life Building, New York City:
New York Building (fictional)
Commerzbank Tower, Frankfurt
Bank of America Plaza, Atlanta
BellSouth Tower, Atlanta:
All of these models with the exception of the Home Insurance Building, are at 1:1700 scale.