Xyngi/Bagua is what I would go with. Last I heard the 21 foot rule was changed to 30 feet and it was being tested thoroughly in Florida. Thats what I read b4 deploying back to Iraq last year.
With soc-ital behavioral changes, one does not see 1 on 1 combat that often, in the case where one is being attacked in a robbery perhaps, mugging instance...
but in home invasion, or bar/street fight
I'd never rely on anything that required me to take it to the ground, you are asking to be attacked and dog piled..
Muai Thai, Krav Maga,any of the 'brutal' or kill zone arts. Its more of the person than art. A palm to the nose will kill a man, so Krav Maga has science to it. But, you get guys like Mas Oyama who are simply above and beyond the style they practice and still can kill.
Russian Systema is pretty practical in real fighting situations simliar to Krav maga but easier to learn... On the ground I think its proven BJJ. Standing Thai boxing with a Close combat fighting system like krav maga and brush up on traditional boxing and your goooooood toGO. But they are ALL useless if you cant stay CALM and let your emotions and rage take over,, u will lose.
Sorry bro, maybe 5'. LOL. If you're 19'away ill blow your mother fucking head off. No contest. Game over. Have a even th old cowboy knew to make sure tht u had room to shot plz dont act tuff just listen u might learn something