We had a user asking for the ability to store reports indefinitely. Here is a way you can do that.
In a previous Service pack we added support for Scheduling of reports and getting it delivered to the inbox. In this feature, reports get generated and get stored in the <AppManager_Home>/Reports folder. It is never deleted by Applications Manager. This could be an option to get really old reports that are no more stored in the Applications Manager DB, if there is a need.
The downside: if you think you see a surge in the disk size utilization after configuring Schedule Reports, you may want to schedule cleaning up this folder once in a while.
Hope this helps.
Cheers !