Ever tried using the commandline -green_generals (not sure if I typed it correctly)?
It does somewhat what you asked for. If I'm correct it doesn't reset all V&V's, but does some. But the next general in the line gets less stars etc aswell. So the generals will become poorer then their predecessors.

To get the -green_generals commandline working:
- Rightclick on the shortcut used to start the game and choose Properties.
- You'll see the Source, which will look something like this: "E:\Medieval - Total War\Medieval_TW.EXE" - This is where I got my vanilla MTW installed. So yours might have a different origin.
- Put -green_generals behind the line like this: "E:\Medieval - Total War\Medieval_TW.EXE" -green_generals

Furthermore I don't think you'll be able to mod what you requested. I think it's hardcoded.