I'm curious about the semantics here: what's the difference in your mind between X rated and NC-17 rated content? In my mind they're the same thing or even reversed from how you have it, since NC-17 was the movie rating that replaced X due to X becoming associated with pornography. Not nitpicking, I'm genuinely curious where you're drawing the distinction.
As for programming, I think that's a great idea to have adult-oriented panels. The problem there is that Fanime panels are submitted by attendees unless put on by a guest, so there would need to either be someone willing and able to put on similar panels. It's too late this year since panel applications have closed, but maybe you can find people willing (or do it yourself?). The other option would be to push for Fanime to have adult-oriented guests who can provide similar panels, but....well, I don't see this con doing that haha.
As for programming, I think that's a great idea to have adult-oriented panels. The problem there is that Fanime panels are submitted by attendees unless put on by a guest, so there would need to either be someone willing and able to put on similar panels. It's too late this year since panel applications have closed, but maybe you can find people willing (or do it yourself?). The other option would be to push for Fanime to have adult-oriented guests who can provide similar panels, but....well, I don't see this con doing that haha.