In a recent SQL Down Under show with Jessica Moss, we discussed the need for reports on reporting services itself.
Tim Schmidt from Data Aspects pointed out the following set of reports: http://msdn.microsoft.com/en-us/library/ms161561(SQL.90).aspx.
He noted that they are installed as part of the SQL Server samples at:
<drive>:\Program Files\Microsoft SQL Server\<version>\Samples\Reporting Services\Report Samples\Server Management Sample Reports
and available from CodePlex. Also, that they aren't pretty :-)
Thanks for the feedback Tim!