Cant diagnoise a front end creeking noice- like a creeky rocking chair

I have a 1999 Lexus GS300- this creeking noice is coming from the front and I have had several mechanics look at it and can not locate the problem. This noise is random and comes at will. The car does have to be on motion to hear the noise. One mechanic said maybe it was the struts but that does not sound right. I cant imagine this to be a good thing- I need to identify and fix- I have had the brakes- frontend- tires- checked. What else