I see little need for trainer for this game.
It's pretty easy to mod it so you get anything you want easily.
Just go to the Common folder, and find the static_modifiers file, choose the difficulty you usually play on to modify (and I suggest this to be the easiest one, so you could always choose whether to cheat or not), and place there all the modifiers you want (some you can find in the same file, others you will find across the rest of the files) with the values you want.
I've made it so I always instantly create all units&ships, get obscene amounts of money, easily convert any province to my religion, my army&navy get a huge bonus to their effectiveness, I research very quickly and more.
In fact, the main problem I encounter in this game is that I get so much money that ever once in a while if I don't save the game, quit and edit the saved game to change my money to something much much lower, I sort of get an overflow of the variable holding the money, and end up with with a negative amount
(In the past I was thinking of trying to create a special event for the game that will automatically lower my money whenever it gets too high, but I don't play this game much lately and can't bother browsing the official forums for instructions on how to do so).
Hope this helps,
Enjoy!