This is why I'd like to be clever enough to design and build my own headphone, it would look very similar to the HE-90 but with a wider headband, only the very best leather would be used, the metal would be titanium for lightness and strength then powder coated in matt black and the wood would be amboyna burl. I hope Sennheiser or Stax headphone designers will be told to look at this post and do something about it.
No matter what the product there is always a place where they cut corners, always. I was going to buy the set of all leather pads a few years ago for the HE90's made by a sponsor on Head-Fi but they could not produce them for some reason. Hell even when you upgrade the interior of a car to leather you only get it on the seatng area of the front seats and gearshift knob and steering wheel, that's it. The other 85% of the interior is vinyl; talk about a rip-off. I can't think of any headphone designer that takes a cost no object approach as you're suggesting and I doubt they ever will. No offense at all, it's just reality. Gary