I know this predicament well. I figured I could give them away when they were old enough, but then I named them...and got very attached to them...so now I am the "mom" to 12 rats, that I have turned down giving away more than a few times. I just don't think that anyone else could spoil them as well as I do. But as I posted before, I am pretty sure dome Monday all the males will be fixed and I won't find myself in this spot again.
You should re-consider breeding, since you are having a problem finding homes for the ones you already have.