I just called Dillon.
YES ! They are making one. It will be available before the end of the year and retrofit to existing 550 and 550B's.
No hard cost figures are published, but the fellow I spoke with indicated $2-300 is what he's been told.
That's a lot of cash for a feeder, I will let someone else ginuea pig it first and see how it works, then probably pony up the cash and get one if initial reports are good.