If this project is still underway, I have a suggestion for the leader files. I'm not sure if anybody still has this game lying around, its about 10 years old, but it was made by KOEI, who also made Romance of the Three Kingdoms which simulaed ancient Chinese struggles. The game was called L'Emperor and was both a strategic and tactical game dealing with the Napoleonic period. Every leader you could ever want for a Napoleonic version of EU could be found in this old game, Prussian, French, Russian, English, Spanish, Turkish, Austrian, and a whole host of other minor nations. Like I said, I'm not sure if there are many copies of this game lying around out there, but this is my suggestion as how to compile a complete database with ratings a quickly as possible. Otherwise, you'll have to rely on scouring the OOB's for nations and getting leaders from there. Best of luck on the project.
