Jon, forget non-lethal ammo. You are just courting a law suit with less-than-lethal ammo.
If a situation deteriorates to the point where one is forced to use lawful deadly force to protect oneself (or others), then one must terminate the situation, period. Only John Wayne just shot the bad guy in the arm and he is... Dead. Hollywood theatrics don't work in the real world. If you wound, cripple, maim someone you will be accused of willfully torturing that person even if that person was in the wrong. In other words, his attorney will say that you used less-than-lethal force because the situation did NOT warrant you defending yourself AT ALL. Therefore, you just tortured his client because you possessed the means to do so.
If your life and well being is placed in jeapordy, you can't toy with the wrong-doer; lethal force must ONLY be resorted to in life-and-death situations. If a crazed/drugged up felon breaks into your home intent on who-knows-what, do you want to just shoot him with a rubber bullet that will only add to his rage? Do you want to 'shoot him in the arm?' Do you want to bluff him with a blank pistol?
If you feel the need to arm yourself to keep yourself, your family, your home safe, then do so. Pray you never have to resort to deadly force, but if you do, pray you are the one who survives. If the bad guy dies because he placed you in that situation, then that is really too bad, but he never should have placed your life and well-being in jeapordy.