Is there a way to get the original data used to create performance charts?
As others have stated, the data certainly exists but the manufacturers are under no obligation to provide anything more than what's in the manual.  

That said, the performance equations are straightforward and with some effort you could build the tables.  What you are proposing exists for most air transport aircraft for their Flight Management Systems.  

As a reference, you might check out Getting to Grips with Aircraft Performance.  It's written by Airbus but provides a very good explanation including much of the math.