How about sponsors that only offer 50% but bill there customers in the customers currency - and i'm not talking about a straight USD conversion.
For example:
US surfer gets charged $25 USD
EU surfer gets charged 25 Euros (approx $40)
UK surfer gets charged £25 Pounds Sterling (approx $49)
Those non US sales you make will earn you more per join/rebill and more programs are doing this now
