I'm not sure this would work but i'm going to suggest it anyway... I think if you put a tag on your photo/scrapbook stash items, and then do a search with Windows...
start/search/all files and folders/ and then enter the tag in the *A word or phrase in the file* and then scroll down the dialogue box and navigate to where you want it to search.. I would locate all the files in that set of folders/drive that have the tag words in the file. This would then not slow your PSE down as you're not using it to locate a file. You then just drag the file to into PSE.
I can't test it at the moment to see if it works well because I'm backing up my entire system.. and I've got only 20% CPU to use.. which means I can't open ACDSee or PS or Bridge.. as they are memory hogs.. so can't tag anything to test.. but the theory makes sense because I know you can search on date. I'll test it later.