So on my fallout 3 game, I had a mod installed that allowed me to have a few more followers, but it didn't increase the companion limit, it just added more companions to the game,
here's the link and I just wanted to say though, along with having them along, I think it would have an awesome idea to have Dukov (as womanizing as he is) as a companion, and the mechanist so he can "rid the world of evil-doers, like the ANTAGONIZER!!!!!!!!" yadda, yadda, yadda, so if someone can do that, that would be awesome