Back in OS9 I used the Finder to accomplish this purpose. It should still work in OS X. Here's how:
1. Create a folder and name it to correspond with a CD or DVD disk.
2. Stick that disk in the computer and open it up in the Finder. Select all the files on the disk, and then option-command drag them into the new folder on your harddrive. This will make aliases to the files on the disk on your drive.
3. Eject your CD or DVD.
By doing this after you burn the disk, you have a mirror image on your drive (without all the space, of course). I believe that if you double click on one of the aliases, the system will ask you for that disk. (At least that's how OS9 handled requests like that).
The Finder then serves as the database. Panther's fast search makes this feasible, and it should only get better with Tiger.
Hope this helps!