From what I've seen on expired Yahoo Auctions, last year they were going for 20k-30k yen. There was one in January this year for around 50k yen. And now thisfohat wrote: ↑Weren't these prices commonplace a couple of years ago?
Prices on truly scarce and desirable gear tends to "roller-coaster" considerably over the years, from my observations.
My theory is that people in the west got more exposure to these boards this year, partly owing to DT as well, and now they are treated like an even rarer SSK with an added bonus of a short spacebar. (At least I didn't even know these existed until some two months ago. But then, again, I didn't know a lot of stuff back then )