Globally Distributed IP Addresses Needed

Hi Folks,
I hope this is the right forum for this question.

The company I work for needs to have globally distributed IP addresses in order to emulate local search results. In other words, if we have a client in London who wants to analyze search results in that particular market, we want to be able to emulate the search results in London (Note: we are not located in London, nor the EU for that matter). So, I think we ultimately need a proxy server in London. What is the best way to accomplish what we are trying to accomplish?

Thanks,
Dennis