The S.F.S.O.'s website shows that this will be released in August. I'm quite certain that Harmonia Mundi will get it out to retail stores at the same time. Unless my math is wrong, MTT has definitely become a tad slower in the 8th as well. I get 23.5 minutes for Part I, and a full 60 minutes for Part II. Maybe somebody could double check my addition (and division). Regardless, nearly 28 minutes is slow enough for the M10 Adagio. But hey, at least they wisely put the M10 Adagio before Part I of M8.
http://www.shopsfsymphony.org/shop/product.php?productid=1510And be sure to also order the J.S. Bach action figure shown on the same screen, since the Mahler 8th - quote - "owes a great debt to the towering Baroque choral works of J.S. Bach".