It sounds like the same issue I had. My 02 now has 35K but the dash rattle started at about 15K. I found it was the driver's side air vent on top of the dash. Hope it helps.
Oh, and I just rolled up a bit of electrical tape and placed it between the dash and vent. It's invisable to the eye & the rattles been gone ever since.
Best of luck,
Jimbo