If you want something that's hilly but maybe not quite as bad as Griffith Park, then I would recommend going to Topanga Canyon State Park in the valley. I wouldn't neccessarily call it "rolling hills" because that makes it sound nice and leisurely, but it is probably closer to what you're looking for than Griffith.
If you go to the trail at the top of Reseda Blvd (South of Ventura Blvd.) you'll find a good up and down dirt trail. Head left to run the good part of the trail. However, there really isn't too much flat, just up or down, and the hills can be tough if you are running HARD. You do get to run by an old missile defense tower though, and the trail has great views of the Valley (and sometimes the ocean and downtown if its a clear day) so that's pretty cool.