I´m interested in this subject as well.
What´s the best way to create a custom admin page? I my case I want to include an administration for an seperate mysql-table (which has nothing to do with PW itself). I would like to have an additional link in the backend navigation which sends the editor to a page where he can insert / edit the entries. (I would just include simple forms and sql-queries to realise the functionality of inserting/editing)
Another idea related to this topic:
Is it possible to "outsource" one part of the PAGE-tree in the backend to a seperate page called ARTICLES or what ever? I would like to administrate my news- or staff-section for example in an own backend page because of the overview when the whole page gets larger and more complex in its number of pages.