Hey desemejante,
I have a similar profile to yours (BSc Economics - LSE). I have been checking out options for a terminal MA economics program in the US (not interested in a Phd at the moment) and have come up with the following choices:
NYU
Duke
Boston
Columbia QMSS
Since iv taken quite a few finance courses, I also applied for the Princeton MFin.
Havent been able to discover how competitive they are either. If you do manage find out, please let me know.
Cheers