GURPS Age Of Napoleon is about the only one I know of. You could mine d20 Past and Skull and Bones for some ideas though.
It could a very interesting campaign setting. You could go in so many different directions with it. Naval Adventure (Captain and Commander stuff), Espionage, Military, etc. You could even add some Horror elements to it (think Brotherhood of the Wolf). A game set during Napoleon's invasion of Egypt would be very fun as well!