2 Techniques posted do exactly that and the 3rd system posted AKK has many, if not most techniques taught off a single strike - Initial reasoning in Shaolin Kempo is to teach where to hit and with what to hit not to make it look like a real fight. Sparring and sparring drills are more the area for defend/counter/defend/counter type of training, but pieces of Combos/DMs/Kempos/Forms can be broken out and used in the same way. I can teach someone to play football by putting them into the game their 1st day to make it "realistic" for them or I can start off with basics and work my way toward reality. In my opinion SKK is often taught with too much dependence on sparring to develop the reaction side of the system, but if an SKK instructor does a good job teaching people in the sparring ring then the Combinations can be thought of as the building blocks to get a person ready for the sparring portion of their training. Me personally I like lots of drills to bridge the lack of reaction needed for most combinations while decreasing the amount of variables a student has to deal with in sparring. Many people may say on a combination the person is being hit and the body is being manipulated to bring them into the next move. I agree with that, but it is the initial hitting of the attacker that is the weak link for many. You can't get to the end unless you have a great beginning. In my opinion back to lots of drills and working just the very beginning of the combos.Your opponent throws 1 punch. You counter with 5 moves while he is still frozen in his punch. Is this realistic? In the normal situation, if you make 1 move, your opponent will respond with 1 move. When you make your 2nd move, he will respond with your 2nd move.
Unless you are 5 times faster than your opponent, this kind of training is not realistic IMO.