When having several currency there is an issue with payment procesor.
Lets say there are two diferent currency COP and USD and client goes with USD.
USD with lets say 2checkout will process normally and api url does well.
But if its COP price once 2checkout out gets price in COP it wont be...
I have been looing into this topic as well and have thought of something:
Maybe consider packages to have option for setting aditional currency but in the same package.
When in the url the currency is set it shows currency, this method has no currency convertion.
Its just an idea we believe...