I've been spending the past few days with Eclipse and BIRT. Their examples and screencasts are quite valuable to understanding a fairly complex application. I suspect this model of documentation is quite applicable to CiviCRM also.
I'm making pretty good progress with CiviReport and currently have a BIRT library with various reports that can be distributed. I'm focusing on CiviContribute for the initial set of reports, but it is quite easy to adapt the reports to CiviMember and CiviEvent. BIRT allows you to have drill down reports (i.e. from a high level report, you can get more detailed reports on various aspects by drilling down a level or two). Thus a top level contribution report could give you breakdown by year, state and your top 5 donors. You can then drill down into details for each year, or state or a more detailed contribution report on a donor.
There are a few generic reports that we will create and distribute. However reporting is quite user specific and would be great to actually design and develop detailed reports for a few specific users. If you have a user who you think could benefit from CiviReport, please contact me offline and we can do a test deploy etc. Here are some basic requirements:
Please contact me off list if this might be of interest to you