TKM, I think you're correct about the County Line brand. I believe they are made for TSC by KK. Something to keep in mind, the KK tillers will dig in and really load a tractor down. My brother had a B7500 and a 4' KK. His garden spot was rich deep top soil and on the first pass it would dig so deep his tractor wouldn't even pull it in 2wd. Before he got a tractor I always dig his garden with my Bushhog tiller. His would do in one pass what it took me two passes to do. If I had it to do over again I would have bought a KK myself. Having 6 tines per row makes a huge difference over a 4 tine like mine. Like I said though, it takes some HP to run one but they are efficient.
A guy down the road from me replaced his worn out Long tiller with a 7' KK. He has a IH 585 tractor which is around 60 hp I think. The first time he used the new tiller he went in the field like he always did at a low rpm and it killed the engine. He tried again and it killed it. He tried a third time with it about 2000 rpm and when the tines hit the ground the the black smoke was rolling and the dirt was flying. I was very impressed.