Very nice article and great job on the reports. Wasn't sure if you were aware of it at all, but with the SSRS Samples on CodePlex there is an SSIS package and Reports that you can leverage, Report Execution Log Files. Doesn't provide everything you have provided, but you might want to check it out if you haven't seen this before. The only reason that you would want this is because you will want to offload the Execution information since the default setting is to only keep 60 days of history.

There are other Report Packs available for SSRS 2005 that you can check out here on the Microsoft downloads SQL Server 2005 Report Packs.

Thanks for sharing your work. Once again very nice.