i'm pretty sure you can UNLINK everything in one go,
and you can SLIP or MOVE all audio or pic in one go,
but you have to RE-LINK one by one.
that's in FCP.
Andreas Keil from Spherico Filmtools once made a small XML app which would link an entire FCP timeline.
i cant see it on his site.
might be worth contacting him if he doesn't see this.
nick