My Panda has three rattles from around the dash area: one, like many others reported here, only happens when its cold in the car, and goes away once the heater kicks in. It seems to relate to the join in the plastic of the centre console, somewhere above my left foot; another I had thought was the instrument panel but I realised yesterday while driving home that it actually comes from inside the indicator/lighting stalk -- applying the slightest pressure to the end of the control stops the rattle. The little button on the end of the wiper stalk for controlling the trip computer has the same problem. The last only seems to happen with a certain set-up of the ventilation controls, temperature, and road speed, when I can then hear what sounds like one of the 'flaps' that directs the air somewhere in the dash area just knocking against something.
But none of these can compare to the total rattle-fest that is my Multipla !!