Need to design a tutorial framework

There is a huge need for something that would make it easy to design tutorials. As I see it, a tutorial is a step by step document leading the viewer toward completion of a goal, whether it be the design of a graphic, a game, some code, or any process realting to graphic and web design.

The system I envision would present the author with a series of nodes that could be text, image, or video. Text would be written instructions/links, Image would be drag and drop or upload from computer, Video would be screen capture-either a selected window or the entire screen.

The tool would allow authors to create tutorials as needed, store them, present them, password-protect them, even sell them.

The biggest issue with tutorials is that they are difficult to make and wildly inconsistent-two tutorials on the same subject can contain a completely different structure. This tool would  make it easy and establish a framework for tutorials.