Also I posted my opinion on it but it wasn't on an HD800 thread, it was in the HE-1000 thread: http://www.head-fi.org/t/748334/hifiman-he1000-planar-dynamic-flagship/7110#post_12301358
still relevant to this thread
I've linked the first message, the teaser, then goes the details, though still without the name.
Declaration: I'm not working for the company that is selling it, I just happen to be a Ukrainian + Patriot and I've been to the store where they officially distribute it and checked it out through different cans, I haven't tested HD800S through them, though I did try it in general, but through the cans that I did use there, the HE-1000 and LCD-3 (Of course to compare how much different the HE-1000 are from my LCD-3's) and I was really pleasantly surprised with this setup.
It was like being transported into a different dimension where the music surrounds you, it's only you and the music, the different elements, 3D Soundstage and Imaging was jaw dropping, I had to say stop at some point because it was getting late there yes I spent about 2 hours with it pretty much alone in a quiet room, was a quiet day that day at the store
But yes, I swear it's good. I'm comparing to my own system right now which is also not bad.
The device in question costs $2500 I wouldn't be surprised if they would up the price, though that's not how business works