Hi,
I have created and managed PPC campaigns for businesses of all sizes for the past 8 years. Whilst managing the PPC campaigns for Rackspace Hosting I was required to create and manage campaigns targeting 15 countries around the World. I was given an overall budget and working to a CPA target had to allocate the budget across all campaigns.
I would be happy to answer any further questions that you may have :)
Kindest regards,
Royston.