Dave Beck is not likely to be making them any longer. Interestingly, he participated in a long WSK thread where he specifically authorized anyone who wanted to, to make WSKs themselves, that the design was for everyone. This was in strong distinction to Tom Brown and TOPS, who want to maintain a monopoly on the design.
Roger Linger has had problems keeping up with orders and I believe he stopped taking them a while ago.
Mark Terrell and Red Scorpio 6 also ran off a few good ones. I don't know of anyone prepared to make them now except for Dan Koster, who also has a waiting list, but ... he is also very open to custom work, and can modify his own ideas to suit your needs.
As I recently found out for myself, getting one of his bushcraft knives, he does VERY nice work.