If FastLane, host of this forum, doesnt carry them - hood pads are generally all over e'bay car parts- mercedes.

The waffle design is probably the most effective, you can buy one on e'bay at/near $35.00 - but am thinkin DIY'ers would have equal success with any high quality sheet of thick foam rubber, possibly gotten at building supply for less than $12.... thats probably what e'bay aftermarket entrepreneur/sellers do anyhow.