Pulleys / Cable / Rope / Winch system

A couple of suggestions already mention winches and cables.
I'd like to see a system that includes pulleys or block and tackle that allows the user to change direction of the cable as well as add mechanical advantage.
Mechanical advantage is more realistic than simply a more powerful winch and will allow finer control of movement which might be useful in low gravity locations
The designer page could allow the user to select length of cable, number of pulleys, and a winch (not required. Pulleys would be attached to the craft or each other and the cable ends could be anchored to user selected parts.