You're welcome.
Cello isn't quite my forté, in the time I've spent with the A2000X I've been swept away by violin, vocals and my electronic music, I think I should leave that answer to a more avid Cello listener with more equipment than I, for example a Denon D7000 or AKG K701, such a person would have better advice/insight.
My only aesthetic complaint with the A2000X is the Clarino earpads, I recently ordered L3000 earpad replacements for them which haven't arrived yet, however the L3000 earpads are made out of Italian lamb skin so that should feel much nicer, if you're interested you can order them here
http://www.audiocubes2.com/brand/Audio-Technica/product/Audio-Technica_Replacement_Pads_for_ATH-L3000.html which will make them look something like this: (this picture is using W5000 earpads)
For other Japanese imports, well I have my eye on the newly released Fostex HP-A3 headphone amplifier, it's made in Japan and I trust Fostex as a brand, it's also receiving very high praise in Japan, so I'm going to order one myself soon, hopefully it has good synergy with the A2000X, one user said is has a very natural tone so I'm looking forward to that myself, it's available on
www.amazon.co.jp and I'll be using
www.tenso.com as the forwarding service since amazon.co.jp won't ship directly outside of Japan.
There is also the slightly more advanced unit, HP-A7.
One source and good synergy I can recommend for the A2000X however, is the Teclast T51 DAP, listening to classical Flac files on max volume directly out of the headphone-out jack is truly a blissful, reference-quality experience, I hope the Fostex HP-A3 can eclipse it, but that is pure speculation and experimentation on my part, I bought my T51 here
http://www.houseofdap.com/teclast-t51-hi-fi-quality-3-5-inch-mp4-player-8gb.html
One of the very first pieces I heard on the A2000X was Julia Fischer playing Vivaldi - L'inverno part III, using T51 as the source, and I was hysteric.
Well, in my quest for reference-quality eurphoric sound, I think this is all the advice I have to share, and I love sharing it, thanks for reading.