Just one quick correction, I do not live in a big city, I live in a small city. However Portugal is a small place and the roads are actually very good meaning going to a bigger city and find out something is not difficult. In order to answer your questions, first there is competitive sambo in a nearby city, there is a federation there, but I think their focus is competition. Regarding the karate dojo and the krav maga gym, the karate dojo is well estabilished here, I think it is older than me. Regarding the krav maga gym, they don't focus in krav maga, they are a regular gym (aka a gym where you go to bulk up) they just happen to have krav maga lessons once or twice per week. The martial arts scene in Portugal is well developed, I can find anything here, capoeira, muay thai, karate, whatever you want is within my reach. I am not sure about the quality of the gyms, I told you before I must focus first in finding one or two martial arts that suit me and then focus on finding a job because there is a lot of gyms, and I do mean a lot.