You could try maksim or rakuten, they are both out now, but rakuten has been rolling through quite a few shig's lately, i believe maxim has a mailing list for when he gets them in...jww doesn't update, so it always looks like they are in stock...good luck! Rakuten currently has nakiri, yanabiba and petty's in stock.
Japan woodworker looks like they have them on their website, as has been stated before. However if you call or e-mail them, Coleen (I think that's her name) will e-mail you the list in stock. Having said that - they've never had a gyuto in stock when I've checked - but they have had some yanagis.
As everyone has already suggested, Maxim has a separate Shig e-mail list. Sign up for that list. He sends it around when he has stock - and then it's a first come first serve that goes extremely fast (we're talking hours ). Good luck!