Found a store while traveling on business in HK, which carried:
- The entire high end Sennheiser line including the HD800 on display, 650, 600, 598, 595, etc. etc.
- The entire Shure line up to the SRH940 (the SRH1840 isn't out yet anywhere)
- Probably the entire Beyerdynamic line with DT990s on a display stand in front, DT880s, 770s, and others
- High-end looking Sonys but I don't know how many because I wasn't interested
- Denon D2000, Grado Alessandros, AKG 271s, and a bunch of others I saw and tried a bit
Another store not far away had Audeze LCD-2s but I don't think they had them for demoing. Seriously that place was amazing for headphone audiophiles. Basically a store of nothing but headphones.
But sadly, literally everyone I saw walking around there with headphones had Beats. Even suited business-people. Arrgh.
Anyway I finally got to try the HD800s, which are simply incredible headphones. The most amazing soundstage, detail, instrument separation, etc. I have ever heard. Anyway... maybe some day.