Well at the time when I started there was none. One of the companies I flew for asked me to give training to some individulas that where flying their airplanes around the world.
I have given several courses to date on international procedures, obtaining overflight permits, oceanic procedures, fuel management and all things relevant to flying a light aircraft over big ponds such as Pacific is.
I do not know if anyone gives these type of courses anymore but bigger training organisations such as FlightSafety and SimuFlight give International training . This is more to the Bizjet and Airline type of operations and does not really cover the elements you encounter at lower flight altitudes and with generally lower performance aircraft than a GV is.
JJ
Should you have any particular questions,I ammore than happy to share information with you all.