All that being said, i am ready to see some extrapolation examples.
Well, I'll take my best shot!
1) The Plague--total mortality estimates range between 25-40% of the world's population;
2) The Spanish influenza--total mortality estimates range between 1-2%.
A 1-40% mortality of a new pandemic would yield 60,000,000-2,400,000,000 deaths.
Of course, many of the deaths due to the 1918 flu were due to complications: pneumonia, etc. Many of these would be ameliorated by modern health-care techniques--but would modern health-care facilities have the capacity to deal with such an influx of patients? The aftermath of recent catastrophes would suggest not, at least in less-industrialized countries.