Fully worked out software design examples

Seeking: Full software design examples

Interviews often ask open-ended design questions like "Design a spreadsheet program". The expectation is too draw a UML-like diagram with program elements like Cell, Toolbar, Menu, MenuItem, ... should demonstrate knowledge of the Model-View-X pattern, etc.

Is there any good repository for such application designs? Ideally, such examples would also include explanations like: Cell is implementing the Observer/Observable pattern; MenuItem takes a Command item which implements the Command pattern.

Most available information is on the level of individual Design Patterns. That is, how to implement a specific Pattern like Command. I have found scant examples of full systems. It seems surprising to me that such questions are so standard and yet fully worked out, real-life sample artifacts are so difficult to find.

Though it doesn't include UML diagrams, here's one great design document which I found: http://ift.tt/1xEuSG6