We've broadcast sunflowers before with good results, should be similar to corn. I think buckhunter is on to something because you need to get the seed deep enough for it to be effective after it's spread. We use a length of chain link fence with a tractor tire on top of it and I think it helps get the seed a bit deeper to get better germination. The fence is about 8 feet long, put the tractor tire on top and wire it on, you could use anything that is heavy and can be attached to the fence so it doesn't roll off, it seems to work the seed into the dirt better, then we pack it with our roller.
msbadger, I really like the idea of using the cheaper feed corn for food plots, but I wonder if there's any way to tell how many days it takes for the corn to mature. One of the more popular corn seeds used up North here are a 90 day maturity kind because our growing season can be pretty short. I know some are 120 day too, and I don't think it'd work for this area.