Rev It Up

I have an E55 K3 and it is terrific. Unfortunately, I have a squeak that sounds like it is coming from the right side of the car. Only happens over bumpy roads, but it is very annoying. Has anyone dealt with squeaks that seem to be coming from the car's structure? Any common things that anyone knows about? The dealer has already had the car 3 times and can't track it down. I guess I could always crank up the tunes if I can't figure it out. Thanks for any insight.