Does Premiere have a way to collect the various original project asset files that for one reason or another were not properly collected prior to importing? What I'd like would be something similar to InDesign's package feature which, at the end of the process, will gather all used assets from their linked locations and place them into a new folder.
The Project Manager can be used for this purpose. You'll find it at the bottom of the File menu.
It works best with self-contained clips like AVIs and .MOVs, not quite so well with folder-based content like P2.