I've had both things myself, once some lugs on a rear wheel not tightened properly and another time my newly built exhaust didn't clear the trans crossmember by enough. But that is ruled out already. I guess I might get my wheels rebalanced, the driveshaft is straight, U-joints are new.
But another question about this rattling: How would timing create a rattle? How would I change that situation?
Thanks for your help
Max