As has been pointed out rattles can be so deceptive where they're actually originating from. I appreciate I'm 2 (or is that 2.5 generations
) behind you all.
But recently after many months of driving me nuts with a rattle on the front passenger side that manifested between 60 and 70 MPH. I found that it was the plastic cladding that clips into the passenger front wheel arch liner that was the cause of my passenger side rattle. It wasn't seated correctly and was rubbing and vibrating through into the cabin.
Previously I'd had the passenger seat, door card, glove box out, A-pillar trim etc to no avail. The rattle was actually on the exterior of the car, so it may be worth a check of the car's underbody plastic trim before stripping car dashboards out in your attempt for sanity.
