JonCat,
I too was trying to find the KK 50" at TSC. The one here in Asheville said "we don't carry that". I went to one in Spartanburg and they had a brochure that included the 50, 60 and 72 inch ones. However, she couldn't get me a price on it, it was a Saturday so she said she couldn't call whoever it was to find out. I had started a thread on this and somebody responded that they got the KK 50" from TSC, so apparently it can be special ordered, if the people that work there are willing to. I believe the person also said it was a lot more expensive than the 60", like $1400-1500, probably because it was a special order. Anyway, if you are looking for one to put on a BX, keep in mind the KK 50 weighs around 600lbs, which is significantly over what the book recommends. In fact, it's very near the maximum lift capacity at 24" behind the lift points.
I ordered a Caroni 48" tiller. The shipping weight on it, with crate and attached to a pallet, was about 420lbs. The Caroni site put the weight at around 407lbs. I'm hoping that it will work ok with my BX. It's supposed to be delivered this afternoon, so if the weather holds out, I should know by the weekend.
Kevin