then if you scroll down there're phones like the qualia and K1000
release dates are right next to the marked out price (i.e $4000 January 1989 for the MDR-R10)
^for timeline, if you need any STAX phones like the omega http://www.stax.co.jp/Export/History.html timeline
K1000 (2001) and the qualia (2004) would be for the sound stage. Though the k1000 is stupid-hard to drive (comparable to the he-6 I guess). First to use a 4-pin XLR was also the k1000 I think.
As for the qualia vs r10, people wanted to see if it could scale up to the r10. However, with the qualia, it's a part of Sony's qualia product line of personalized gear. It had a large, small, and medium headband- unlike the conventional click or auto-adjust. For the qualia to get that seal, it needs the headband that fits your head.
The R10 has its reputation as being the best dynamic phone of all time. Lush mids, sparkling highs, and a warm signature if I'm correct. Though the problem is, is that it uses the bio-cellulose drivers that Sony made. Pretty much dead wood inside as a diaphragm. Fail rate with these were pretty high, thus Sony using the liquid crystal polymer (what they use now) and other materials like nano-composite.
SR-Omega (1993) and SR-009 (2011) both are highly detailed/accurate (what the typical high-end electrostat is) and are able to recreate the track very well w/ spatial placement. The sr-009 is noted for probably being the true replacement for the sr-omega since STAX kind of shut down and restarted. The Omega was made in the old STAX time period.