When I spoke with Lincoln Henderson a couple of months back, he basically reiterated what many have already said here. The potstill is ready, but no one expected that Woodford Reserve would be selling like it is today. His point was that if they were to release the potstill now, they would only have enough to service a couple of major shops in KY.
What he has mentioned doing is blending potstill with the Old Forester in increasing amounts, as more whiskey matures. Eventually, (say 5 years) the entire whiskey would be 100% potstill.
As far as the 4 grain mash goes, he only mentioned in the last issue of Malt Advocate that he has been experimenting with it. You must take into account, he was in a world-class BS session with every other KY distiller, so "experimenting" may just mean he though about it or made some sample mashes. Certainly a four-grain mash would be revolutionary in the world of whiskey, though, in all honesty, I don't see any benefit to it. The smokiness/spiciness of the rye would overpower the wheat to the point that it would become another filler grain like barley. I have yet to see any rye recipe Bourbon where the malted barley character is even evident and I don't see how wheat would be any different in a mashbill including rye.