I have a pair of DT250/V6 velours that I never used outside of trying one time. Not sure of the size of the Denon pads though. You'll have to measure them. The DT pads are 4" x 3" to the outside. Shoot me a PM as they have only been sitting in a drawer.
They are these...http://www.buzzillions.com/reviews/beyerdynamic-velour-padded-earcushions-dt250-dt280-sony-mdr7506-v6-reviews
Click on the pic to get a close up.