Would You Watch a The X Factor World Tournament?
 

They did this for Idol around when it first started blossoming. Where a bunch of winners (including Kelly Clarkson who finished Second.) sang one song and whichever had the highest points out of the countries/versions participating would win. (Points were decided by each version's fans)

Though Simon said "It was a waste of time and it made winners feel like losers". He was swirling the idea around for an World's Got Talent. So I'd imagine he could've been thinking the same for X Factor.

It's big enough and has enough versions it could work. Could raise money for charity.

I would watch it

Yes but would the winners of all The X Factor's come back?

Would eventually just turn into another euro(global)vision really

No, wouldn't interest me really.