Spurred on by a tip from @Touchofevil and after a good while of searching I finally came up with a bottle of Jack Daniels Barrel Proof. This particular batch weighs in at a little more than 129 proof and was put in the bottle January of this year. First impression is it's a lot sweeter tasting than regular Jack with also a hint of smokiness from the charred barrel. The burn hits the back of the throat nicely but doesn't linger in the belly. It's also a lot darker in color than Old #7 or even the single barrel select.