Dutch-'Scheepswerf' replaces 'sea port', gets a bonus to naval units production and perhaps some gold bonus. The reason being that in the dutch golden age ca. 1600-1700 they could build ships cheaper then any other place in Europe. China- 'Junker' resplaces 'Caravel' should get better combat value. Sweden- Maybe a unique hydro plant seen that(according to wikipedia) Sweden get 53% of its energy from water power. I would personally prefer that each civ gets atlast one unique building.