Here are some things that were covered at the American Cryptogram Association convention. Questions were asked to both Jim Sanborn and Ed Scheidt at a dinner, I believe after that actual convention where Scheidt was a speaker.
Apparently someone was video taping a portion of it but I haven’t come across it yet.

This was asked right out of the gate…
“how about another clue?” to which Jim replied (paraphrasing) “you’ll maybe find out about that in a couple of weeks or so”.
It was asked again if the letters BERLIN were the city of Berlin to which Jim confirmed again that it is.
It was asked if N decodes to B, Y decodes to E, etc, etc. and Jim confirmed it does. Emphatically. 
Jim Sanborn rattled through the entire crib:
N = B,
Y = E,
P = R,
V = L,
T = I,
T = N
When the same question was asked to Ed, Jim cut in and said “I’m the only one who knows.”
It was asked if N decodes to B or encodes to B, and Jim stated “decodes”.
It was asked if K4 was a “one-off”. Some discussion ensued about the definition of “one-off”, but Ed looked to Jim and said “well Jim, how are we going to answer that one?”. To which Jim simply replied “we don’t answer it”.
Elonka jumped in to remind Ed that he once told her that Kryptos uses a system unknown to anyone on the planet. Ed stated he didn’t recall that conversation, and back-pedaled out of saying anything more.
Someone asked if anything was buried on the CIA grounds relating to Kryptos and Jim said YES and went on to explain how a USGS marker was buried somewhere but was removed later. 
Klauss:Was something placed by kryptos that we need access to to solve kryptos?
Jim: Yes, there is something buried adjacent to Kryptos. Jae and I went back to visit a couple of years ago, and they had removed it, but it is important.
Donna: Well, since it is not there anymore, can you tell us what it was or do you want to wait for that?,
Jim: The thing that was buried is a bronze USGS marker. It was half buried. It had little cross hairs on the top of it.
Jim went on to say that he still believes there’s something to be gained if we study his encryption charts that he released to the New York Times. He talked about how he released those in the context of we all wondered if the misspelled words were really mistakes, but he didn’t elaborate past that. JS was also involved in some smaller group discussions where individuals said he brought up his K1/K2 matrix and seemed mystified no one has gotten any thing more from it.
Unknown: can we solve K4 without solving k1-k3 first? 
Jim: Yes,  but K5 cannot be solved without K4.

I’m sure more was discussed and/or asked but what I’ve included are what most people that were there are declaring as the meat and potatoes of the Q&A. I’ve been searching for what was said about K4 being a “one-off” and what was meant by it but I haven’t found much. Quite a bit of the debate at this point has been focused on JS’s encryption sheets, the USGS marker, and what theories or systems can be thrown out based on the information provided. If I come across more I’ll send it your way.