All I know is that over here in the UK, Hatton vs Mayweather would sell BIG. Hatton is our only PPV fighter since naz quit, and I imagine Hatton vs Mayweather could generate $30m in the uk alone from PPV buys.
I'm sure the fight would be big, but I really don't think Hatton is capable of drawing 2 million ppv buys just in this country. It's not like Mayweathers some huge name to the average guy who could draw astrononical numbers.