You can have more than one trade mission bldg, but you can ONLY recruit the units of the trade mission you chose in the "Mission Event". I have 1st hand Xp since I captured a region which belonged to Saga, which has a British trade mission, But I cannot recruit neither the Royal marines nor the Warrior class Iron Clad which is the strongest naval vessel in FotS! Some 36 odd broad side cannons and 150 Marines on the ship!! I didn't read the Totalwarpedia, before I opted for the American mission... anyways, I love our marines so I always end up picking the American trade mission and US marines, even though they have lesser attributes than the Royal Marines, or French Marines...lol But to be honest I have never faced the French or Opposing US marines / Roanoke class Iron clad in the field or seas.... Hopefully the Shogunate will recruit a French Iron clad and I might be able to capture it :D Presently playing as the Republic of Satsuma. Planning on stopping expansion after I get my 50 provinces, and holding the line and seeing what happens among the Imperials and Shogunate :)