To start, I am not a modder. But will help anyone who can teach. I think Imperator would be the perfect platform to attempt a Vic 3 mod. One of the reasons is the road building mechanics, because it was the latter 18th C that advanced road building kicked off, and then there were the teams that built the railroads. There is also the subtle difference in how goods are handled in the trade mechanics, which again, I feel would lend itself to a Vic 3 mod. Army compositions as well, to have an army design of multiple infantry, cavalry, and artillery types. It's also the only game that has the supply unit(!) which adds more depth to the logistics aspect of the game.

I really don't know where one would start with it, but please if anyone has experience and thinks it can be done, please let me know where and how I can help.