So I was curious and tried putting Denon D2000 pads on the AD1000X.
1. Every part of the frame of the AD100X, including the baffle and diffuser fins, are machine out of magnesium. This is nice especially compared to some other flagship designs - ie: SA5000.
2. Denon D2000 pads with the additional angle seem to make the soundstage a little more natural, and bass seems just a smidge stronger with the pleather material.
3. The removal of the thin layer of felt between the driver / waveguide and the ear also adds just a bit more sibilance to the highs, but more importantly it exposes the driver to things like my long hair. So I did not try the experiment too long.
I'm looking to order some AD2000X pads, probably from here: http://www.ebay.com.au/itm/GENUINE-Audio-Technica-HP-AD2000X-Replacement-Ear-Pads-for-ATH-AD2000X-Pair-/130900186650?pt=US_Replacement_Parts_Tools&hash=item1e7a42561a Just to see how an AD1000X with AD2000X pads sounds like (and if it sounds the same as an AD2000X).