Oh, that's definately better than I expected! Thanks everyone for the information!
Here is the response from Senn for US customers:
The part # you are looking for is 534411 and they cost $65.46 , If you would like to place an order you can call 860-434-9190 ext 210
This is much better than I was expecting. I listen to my headphones quite a bit and for this price, I can see replacing the pads every 2 yrs or so.