Saw the <font color="red"> King Kutter XB </font> 5' rear blade, 4' box blade, and 48" rotary cutter at Orscheln Farm and Home in Bedford, Indiana just yesterday. Prices were $169.99, $299.99 and $539.99 respectively.
I haven't found anything to speak of on the web regarding these implements, not even at King Kutter's site but I haven't checked back there in the last several days.
The box blade's box looked a good 5 inches or so shorter than a standard size King Cutter box blade. Although I am looking for a 4' box blade I will pass on the XB. With some sub-compacts the shorter height of the XB will permit higher lifting of the box blade. My JD 2210 should be able to handle a taller box blade so I am looking at other box blades particularly the BB20-48 made by Midwest..
Unlike some fo the smaller box blades for sub-compacts, the front and rear blades are not welded. They are bolted on and reversible so that is a plus.
The rotary cutter is of interest to me because I am in the market for a 48".
Quality-wise the XB implements looked about the same as the regular King Kutter "yellow" implements.