I would have thought that the closest thing to Plus-x in the MP range would have been MP Plus-X, not Double-x, but I know they are all a bit different, and it depends on what qualities you are comparing. I shot about 800 feet of Double-X back when you could still find short ends. It's nice, to me it seemed closest to the older tri-x, like the the tri-x I shot in the early 80's. They have improved away a little of it's character since then. Anyway I would love to see them do something that would be very easy to do: 35mm 36exp. Factory loads of MP stock. It would be great to see some of those other emulsions out there, easy to get and use.