I think what he's looking for is something as easy as a Wii Scrubber, where you just point to a file and it scrubs away all the dummy data. Unfortunately it's not that easy for PS3 Games, however (although I haven't used it yet on my games since I've ripped out the unecessary stuff myself) it seems PS3FTP Client 1.0 posted a few days ago here: http://www.ps3news.com/ps3-hacks-jai...ation-arrives/ might do something close to what you are looking for making it easier for yourself to figure what you can delete safely.
Something that you can delete safely from ALL PS3 games is the PS3UPDATE folder, you can delete the PS3UPDAT.PUP data and save a nice amount of space per game, especially if you have several games that require shrinking. Many things like languages can be ripped easily and safely because they are usually named _FR, _ES, _GER, etc etc.
Edit: You'll want to backup your game first to somewhere else before you start playing around and ripping out stuff though.