If you're going to buy a knife that's made of harder steel, you're going to have to buy a real board first. Because hardness does not necessarily equal toughness. See this thread:
http://www.kitchenknifeforums.com/showthread.php/4772-what-steels-and-why/page3?highlight=toughness
You're right. When you buy a knife on BST, it will probably be cheaper. But you're likely getting a knife that's been personally tailored by the owner, and will likely have scratches, patina, or possibly even some damage. Also, because these knives are pre-owned, they may not be ground 50/50. (In fact, I'd say the majority won't be.)
As for the Konosuke, I tried out a 270 HD Gyuto a while back. They're thin, with good geometry, generally good fit and finish (more recent versions, according to some posts I recall reading, have had fit and finish problems). I can't say much for its durability other than the edge held up over a week of home cook use. But, it's not really what I would consider a knife that can "take a beating"; but, that ultimately depends on what you mean by "take a beating."
If you're talking about whacking through fish and chicken bones, I wouldn't recommend the Konosuke based on my experience. (I don't try these kinds of things with knives that I borrow or try out.) But, I'm definitely interested in hearing from owners whether it's durable enough for this kind of stuff.
