Hi,
After replying to one of the responses of your thread, I went back to the original problem threads. I really feel sorry for your troubles. Going in and manipulating the library within is bad. I'm sorry I didn't see it earlier. Have you tried iPhoto Library Manager from Fat Cat Software?
If it was me, the first thing I would do is get an external USB drive large enough to hold all the copies of the libraries. Then I would get the iPhoto Library Manager and have it create a new library and it will/can copy any metadata,etc (last I heard, not faces,) to a fresh new library. It does not go in and create / manipulate the library directory. It uses some form of scripting to get the file from iPhoto and then relaunches iPhoto to a destination library and imports it.
Look at their website. fatcatsoftware.comIt can copy, merge and find duplicates from the library. They have a demo/trial but I don't know what features are available. I own a full version of it. If you try it, you must copy the photos to a fresh new library. If you have any questions, you can email the author.
I have been using iPhoto since 2004 and have over 36,000 photos. And we use all the features of it, faces,location, slideshow, etc., but I have some pains.
Hope the above would be of some help