I see your objections. My idea is you could base it in the US possibly or have more than one and have them just work out the global earnings using GAAP and apportion it to the various countries by how much they sell there so you get a earnings figure for each country. The countries could then use that to come up with a tax demand at their chosen rate and the company could either pay up or face sanctions in that country. So it doesn't require anything like a world government, just some accounting and possibly trade agreements.