Well the only reason I would do Gran Colombia is so I don't have to do too much work as far as units and city names and such go. I would make the leaders Simon Bolivar and Hugo Chavez if I went that route. I'm pretty lenient when it comes to historical accuracy, the game isn't very historically accurate so I don't feel like I should let that hold me back. That said I try to make it "realistic," in the sense that I won't have fantasy civs or leaders (although I do have Dido, and she may be a legend) in my games. So its kinda strange. I'm almost finished with Gustav Adolph, right now I just know very basic stuff, so I'm pretty much just chopping up other LHs and using their parts at this point. It is very difficult and frustrating though. But I should have a better Gustav Adolph LH for your Swedish Civ ready very soon!
Haha, yeah I also chose Gran Colombia so I could easily represent a large portion of South America without having to make a bunch of tiny civs. It was nice that Gran Colombia technically actually did that. I'm not usually a fan of say making an Asia civ that represents all of Asia.