our team has developed popular FPPlatform (aka, fiverr clone) and SFPlatform (seed/crowd funding platform). I see, here we're facing huge crunch in terms of payment gateway solutions. The least closest here is the solution from PayPal called adaptive payments. But, due to their API design and approval process, there's gap creating (Not to mention that PayPal is working with us to improve that).
Over the top of my head, thinking of creating a payment gateway provider on the top of PayPal or Authorize.net with improved API design (something like Braintree)