I for one would love a JT WB Quadio release, even if it were single BluRay's of his two Quadradiscs, but I have a feeling that will never be.
It's said the old JT and WB still do not get along. If you recall back in the '70s JT left WB for Columbia and there was some serious bad blood between the two parties, and if anyone knows the legend of James Taylor and bad blood (ask Carly), he does not mend fences easily. He may be a great guy and all, and I do love his music (bought everything, seen him countless times), but apparently he can carry a grudge for decades.
In order for WB to release Quadio's (or even a stereo set of his albums), they would need his permission. Honestly, there should have been a stereo JT WB box by now, but it never appeared. That may be a clue. Also, during the "remaster with bonus tracks" CD era, none of the WB JT albums got any kind of special treatment, and there are some things that could have been added to remastered CD's to give them more appeal, such as "Country Road", the 45 version (which is totally different than the album version), and "I Can Dream of You", which was the B side to "Shower the People" that never appeared on an album.
Now, it's true that AF did release Gold CD's of most of his WB albums, and I am speaking with absolutely NO AUTHORITY on this topic (Heck, the JT Quadio could come out tomorrow for all I know), but I might guess that since these were reissues on another label, maybe JT thought that was OK, or maybe he had a relationship with Marshall or AF that facilitated the deal.
Anyway, like Brian and others have said time and time again, there is a lot of things that have to go right for something like a James Taylor surround release to see the light of day.
Sadly.