My clients (which include faculty, graduate students and post-Docs) have received offers from these universities (in alphabetical order):
Australian National University
Chinese University of Hong Kong
Columbia University
Cornell University
Harvard University
Massachusetts Institute of Technology (MIT)
National University of Singapore
New York University
Northwestern University
Ohio State University
Pennsylvania State University
Princeton University
Stanford University
Tsinghua University
University of California, Berkeley
University of California, Los Angeles
University of California, San Diego
University of Cambridge
University of Chicago
University of Hong Kong
University of Michigan
University of New South Wales
University of Oxford
University of Pennsylvania
University of Southern California
University of Washington