Hi,
Having been asked to write a document containing some of these things on a site, I'm thinking of writing a module that basically nicely formats a db dump into an HTML page so you can get a bird's eye view of what the site entails.
This is a great idea. Apart from anything else, as I'm still a beginner I could view such a page and treat it as a kind of checklist: "this is what an advanced Drupaller would need to know at a glance to understand the site; these areas are therefore what I need to tie down before my site can get under way." Would it also be useful (for e.g. complex themes) to be able to get some sort of JavaDoc-like self-documentation out of the templates, as then what you're proposing covers the likeliest locations of both custom data- and codebase? phpDocumentor would cope well with the functions in template.php but I don't know how much use it is for documenting combined HTML/PHP files. Regardless of what gets decided I'm offering a hand. However, I'm still at the level of expertise where I could be as much a hindrance as a help, so I don't mind if I get put on grunt work/testing. Cheers, J-P