Hi Nuru, the one sized for the BX is a 24 inch, it would probably work well with the 4100 also. Their XB line appears to have pin spacing a bit more narrow for ideal hook up with the slightly small cat-1 on the BX. This new line off equipment pretty much ends the -- "I cannot find anything for my BX complaint"---- and I figure that 3-point finsih mower would be a good match for my 2410 also or a 4100ish type tractor as well. In fact I wish I had gotten their XB brush cutter instead of the standard duty model I got. The only thing in the line I question is the boxblade--I think the BX can handle more blade than that, at least mine can.
KK also has a 30 inch dirt scoop at Atwoods, I got to go by there latter, well, I don't have to, but I want to so I will try to get a price if I can. Nuru, you really will eventually bite the bullet and get the loader and the 60 in MMM, you know you want them, you know you must have them, have them, have them, have them. (a little hypnosis)
J