Stefan, I got the map done, and just sent it to you earlier today. However it still needs a lot of work, but its probably best left with you since terrains and atmosphere of the graphics will probably play a big role for the kind of scen you're making. The map got a tad bit wide, but it can be 'squeezed' further if you want, with MapEdit.
Additionally, I'm improving constantly on the graphics work for my own scenario, so you might want to try out some of the new graphics. For instance, I made a new plateau/highlands graphic that looks & feels far better than the old one from the modpack. I've attached them to this post.
I'm also quite satisfied with the 'high grass' savannah, which will be perfect for the 'guerilla war' theme you're after. This kind of terrain was widespread over all of Africa, often measuring up to 8-10 feet, making it very difficult to spot the enemy and easy to hide in, but lethal to either attacker or defenderr, because bullets or arrows fired at random into the grass, could still hit anything in their direction and be deadly.