Wow, it sure is a mystery to me. It's divided into 8 parts, each lasting 10 minutes. That means that this is a relatively fast performance, clocking in at barely 80 minutes. What's strange, is that there's no applause at the end, or any other audience noise what so ever. The sound is excellent, which makes me think that it could be a "studio" performance. Yet, it's clearly not any of the existing commercial recordings out there (or I'll eat my hat!). The playing is excellent. On the whole, the women aren't nearly as good as they are on the MTT/SFSO M8; yet, the baritone and bass-baritone are clearly better (I would say that it's a tie for the tenor spot). The organ is really strong, and the tam-tam is definitely a Wuhan, not a Paiste. That eliminates Eschenbach/Orchestre de Paris. It also eliminates any British performance, unless the BBC Phil. or Bournemouth S.O. are using a Wuhan these days. The tempi are too quick to be Lorin Maazel, and the conducting is too straight forward to be either Eschenbach or MTT (unless Eschenbach has greatly smoothed out his "interpretation" since his Paris performance).
It can't be the Gergiev one from St. Paul's Cathedral (wrong gong, and wrong acoustic), and the sound is probably too good to have been Gergiev's Rotterdam performance. It definitely does not sound like the Vienna Phil., so it couldn't have been Boulez's live performance from the Musikverein (which supposedly has a new organ these days). It's also too fast to be Boulez anyway. It's definitely not the recent Inbal, as that one is already posted on Youtube (and some of the tempi are quite different). So, here a few guesses that I have:
My #1 suspicion is this: it's a teaser for the upcoming Zinman/TOZ M8 release for RCA.
#2: It could Eschenbach/Philly, but only if Eschenbach has smoothed out some of his more eccentric sounding moments. But how would they have gotten ALL of the audience noise out?
#3: It's a studio performance from Wien's Konzerthaus, possibly involving the Vienna Radio Symphony and Billy de Brandt (whatever his name is). However, I think that that performance hasn't happened yet.
#4: Maybe Fabio Luisi recently did it in Dresden. However, everybody would be all over that one.
#5: It's some performance from Scandinavia, involving some new hall that has a rockin' organ. If so, then it could be Alan Gilbert (didn't he do a full cycle in Stockholm?) or Esa-Pekka Salonen.
#6 (and my most far-out guess): It's something that happened at the converted train station in Sao Paulo, Brazil.
Regardless, give this one a spin - it's quite good! It's easy to identify it because all 8 parts have no picture what-so-ever. Also, there are no credits given to the performers at all. It's just one big, Mahlerian sized mystery, captured in excellent sound.