I found a couple great links to Oger Warband Rules for Mordheim. Many of them have not been tested, but I’m putting they up because I found them interesting, and they seem pretty fair.
This first link is a post on Games Workshop Specialist Forum entitled Oger Warband, and seems pretty fair to me. You can only have a total of 3 Ogers. My only real problem with it is that you have to shoot or attack the Ogers if you can. You are not allowed to shoot their weak slaves. I would do away with that rule.
Here’s another link on another Games Workshop Forum entitled Ogre Kingdoms Warband. I haven’t evaluated this one yet, but from briefly looking it over, it looks like this one is very unbalanced. Let me know what you think.