Craig Freier, your fuel figures aren't quite right. Before the 'Green Nazis' latch onto them as evidence of profligate carbon emissions by 'evil aeroplanes' (works of Satan and all that garbage), I think you meant
737- 40kgs/min ie 2400kgs/hr
747- 200kgs/min ie 12000 kgs/hr
In fact we were looking at 1900kgs/hr at the end of cruise in a 737-700 this week, and the 747 comes down to well below 10,000kgs/hr at the end of cruise.