I recently had to create a V-n diagram spreadsheet for a loads report we are working on for a client. This is for part 23 aircraft and is based on the utility category maneuver envelope, but it does show the normal category envelope for comparison.
You can download the free spreadsheet here
Enjoy!
I noticed that the VA speed for positive n (Point A) is the same as the VA speed for negative n (Point G). This is almost never the case in Normal or Utility category airplanes.
Also, since the +1 G stall speed is usually different that the -1 G stall speed, it would be nice to have a vertical line from the origin to each value.