Hi Dave --
I don't know if it's ever going to be shipped out for general sale. I was under the impression it was only available at the distillery's souvenir store, the way the old "powderhorn" bottle was. It might be available only in Tennessee, like Four Roses is in Kentucky.
According to a well-known Hall-of-Fame nominee with whom we're acquainted, and convincingly demonstrated by him to an audience of n'er-do-well's and skeptics (some of whom may be reading this), the ten-year-old originally used in the UD Heritage collection became 11, then 12, and so forth as overproduction caused their inventory to back up. In sample pours, he carefully reduced the #12's proof from 90 to the SR's 86, and no one in the room could detect the difference. That also suggests the even better side of this... that anyone buying (more or less) six-year-old #12, already a bargain for whiskey of that quality, was really getting the same 12-year product -- and at higher proof, no less!
Such a DEAL!
Even today there's probably little difference between the two other than proof. Dickel started the still back up less than four years ago, so without an age statement to the contrary you know there's none of the new product in there. The last of the old stuff came out in 1999, so even if they used only their youngest whiskey it would be seven years, and they probably used older stock. You can see why they'd prefer not to make that age-statement mistake again with the new labelling.
However, in reference to that last paragraph, keep this mind: Why do you suppose Diageo chose to shut down production (for four years -- interesting length of time, no?) instead of just transferring the excess product to another of their brands like everyone else does? The answer is that they can't. Dickel can't be added to any bourbon, because it's not bourbon; it's Tennessee whiskey. In fact, it's not even "straight whiskey". Since it doesn't qualify as straight spirit, and because (despite 63 years of updates and modifications to the federal regulations since Motlow's rejection letter from them) the Treasury department still has not seen fit to recognize Tennessee whiskey as anything special, other than "not straight whiskey", George Dickel (as well as that other fine "D" whiskey from the Volunteer State) isn't required to conform to any specifications that wouldn't also apply to Early Times. It could be (I'm not saying it is -- that's for someone else to find out -- only that it COULD be) bottled right off the still, with caramel coloring and flavoring added, same as every other brown liquor that isn't straight whiskey. It COULD be aged six months on toasted oak (or maple) chips. The new whiskey from Dickel COULD be distilled as straight bourbon whiskey, and then flavored with maple charcoal AT THE TIME OF BOTTLING, so as to allow any future overruns to be absorbed by other brands (since the whiskey would conform to regulation up to that point). To tell you the truth, DEO stockholders (or at least the thirteen or so who believe Dickel to be of any significance to the company) should welcome a decision like that, since it would prevent having to shut the plant down and restart it (that's the costly part) whenever there's a production overrun. In addition, it would also allow them to transfer production of their bourbon product, I.W. Harper, to the Cascade plant instead of contracting it out to Bernheim.