Hierachical Document Structures?

I want to throw a question out to everyone else who has worked in both Domino and SharePoint:

In a number of our Domino apps, we will have a main document, for example a project description, with child documents, using different forms, for example, tasks, deliverables, meeting agendas, etc. Each of those forms may, in turn, have their own child documents.

The final result is one parent document, with the ability to drill down in a view to see all the available child documents at multiple levels of a hierarchy.

So the question — How does one achieve this same type of UI in SharePoint? Is there any way to do it that isn’t either spaghetti code or a maintenance nightmare?