I talked to Justin about it when I ordered my GS-1. The gist of it was that he did build some new modules to test out, but in the end didn't believe they offered enough of a performance upgrade over the original design to justify the extra cost. So I think that's all she wrote.
Love it on the desktop, but the iPhone app sucks for reasons largely beyond their control (sandboxing rules etc.) Their first implementation -- letting you use bookmarklets in Safari -- worked far better and I think they've recently added that functionality back into the desktop version after getting a flood of complaints from whinging ingrates like me.
Very interesting. I've never even considered trying to EQ headphones, as I've always thought of it as a way to deal room modes rather than alter driver responses. Could you post a picture of the setup in action, ie. phones on the "ear" showing mic position?
A lot of people use the ECM8000 with REQ. There are calibration files for it knocking around on the Home Theater Shack site where the software is hosted.