They come up on aquabid periodically.
To the first couple of people that made rude comments, just because you haven't heard of them being sold and kept in captivity doesn't mean they aren't. They're not common, but not unheard of either.
Making snide comments on this website about a rare, large, high maintenance fish is a bit silly considering this site is devoted to people that keep such.
I don't want to threadjack this persons WTB thread, and I won't respond further to the above issue, but I just didn't want the original poster to feel stupid or be driven off the website for making such a request.