Endless rope machines are great. I used them a lot and it is a great tool to build up upper body conditioning, especially in the forearms. I even had a gym membership just to use this machine.
The problem with these machines are that, they are super expensive and they take a lot of space. You can accomplish a endless rope/chain system under 50 bucks. I prefer using chains since they are heavier than ropes. This exercise can be much more different if it is done on ruber surfaces that have high friction.
Below is a video from my mad methods magazine. This video focuses on pulls in plank position. You can do pul exercises standing and sitting as well. You can change the chain length and thickness to increase the difficulty in this workout.